A seawater mixture of nonylphenol-ethoxylate compounds, the number of their ethylene-glycol unit ranges from 1 to 18, was filtrated through a glass column that was packed with different particles. No compound was eluted from a column of hydrophobic-silica-gel particles with seawater. When the compounds were filtrated through a column of hydrophilic-silica-gel particle, the homologues with shorter-chained ethylene-glycol unit were eluted more rapidly than the homologues with longer chain. Elution pattern from a column of silty- and clayey-sediment particle was similar to that of the hydrophilic-silica-gel column. The adsorption of NPEO15, a longer-chained homologue, to sediment particles in suspension was not clearly different between silt/clayey sediment and sandy sediment, even though the relative ratio of surface area to weight is far different between them. Hence the retaining of nonylphenol compounds by sediment seemed to be performed by a mechanical trap in interstices of sediment, in addition to the sorption to particle surfaces.