The soil/water partition coefficient (Kd) of hexachlorobenzene (HCB) ranged from 220 l/kg to 1800 l/kg for eight soils having a wide range of phsyco-chemical properties. Kd normalized to soil's organic carbon (Koc) was found to be 28000plus/minus4800 l/kg. The effect on the apparent soil/water partition coefficient (Kd*) caused by the anionic surfactant dodecylsulphate (DS) was studied. DS present at concentrations above the critical micellar concentration (CMC) caused reductions in Kd* in the range of 3-26 times for most soils and even up 36-91 times for sandy soils. Below CMC, at environmentally relevant surfactant concentrations, Kd* was reduced by a factor of 1-13. For clay and calcareous soils significant adsorption/complexation/precipitanttion of DS occured. At the lowest DS concentration this produced a two-fold increase in Kd*. At increasing Ds concentrations this effect was shielded by the solubilizing effect from DS. Monomer (Kmn) surfactant/water partition coefficients for HCB were determined to be, 980plus/minus190 l/kg and 21000plus/minus1600 l/kg, respectively.

SKEJO-ANDRESEN Helle Bro; 

1996-04-15

JRC12778

https://publications.jrc.ec.europa.eu/repository/handle/JRC12778,