The role of particle size and surface charge on the ability of a particle to migrate in a soil water column was investigated utilizing carboxylated polystyrene latexes. Experimentally, the only latex particle that was stable and mobile in the soil was the highly charged (519 μ eq/g) 0.19 micron diameter latex. Hydrodynamic chromatography (HDC) was effective in determining both concentration and size distribution of the latex particles in the soil water matrix where there was high surface charge (519 μ eq/g) and small particle size, (< 0.2 microns) or low surface charge (7–11 μ eq/g) particles between 0.166 and 0.507 microns stabilized by a polyoxyethylene-polyoxypropylene block copolymer.

Size played a role, with the movement of the 0.166 micron latex equivalent to that of the 0.19 micron latex. Both were significantly more mobile (less sorptive) than the 0.507 micron latex. Soil also had an influence as 0.19 micron particles were seen to be less mobile in the high organic carbon (OC) soil (Catlin) versus a moderate OC soil (Cecil).

A compartmental model based only on sorption described the data reasonably well. The parameter estimates from the model for the sorption constant, void volume in the soil column, and initial latex concentration were a close approximation to those observed and consistent throughout the study.