Polymer-based adsorbents with excellent size uniformity were used as pretreatment media for real environmental water containing numerous contaminants. A comparison of the results with those from an ideal approach with high-performance liquid chromatography suggested that the shape size and size uniformity of the adsorbents were very important with respect to the loading pressure for the treatment of the environmental water. Furthermore, one of the uniformly sized polymer adsorbents realized an efficiency comparable to that of a commercially available adsorbent based on a typical silica-based octadecyl stationary phase. (c) 2005 Wiley Periodicals, Inc.