The preliminary results of a study on the concentrations of aromatic surfactants (nonylphenol polyethoxylates (NPEO) and linear alkylbenzene sulfonates (LAS)) and their degradation products in river waters of Taiwan were undertaken to establish environmental concentrations and to support surface water protection programs. The analytes were determined by ion-trap GC/MS in EI and CI modes after concentration onto graphitized carbon black (GCB) solid phase extraction columns. The highest concentrations of NPEO and their degradation products (total 1,100 mu g/L) were recorded in the river downstream of the effluent discharge from the industrial parks. However, the highest concentrations of LAS (135 mu g/L) were determined in the samples from downtown where the municipal wastewaters were discharged directly into the river. (C) 1999 Elsevier Science Ltd. All rights reserved.