This report describes a scoping study conducted in order to establish whether pharmaceutical compounds may be present in UK estuaries. Surface water samples collected from five UK estuaries were analysed for the presence of 14 pharmaceutical compounds selected from the priority lists of the UK Environment Agency and the Oslo and Paris Commission (OSPAR). The pharmaceutical compounds/metabolites clofibric acid, clotrimazole, dextropropoxyphene, diclofenac, ibuprofen, mefenamic acid, propranolol, tamoxifen and trimethoprim were detected at measurable concentrations in the samples collected. The concentrations of erythromycin, lofepramine, paracetamol, sulfamethoxazole and acetyl-sulfamethoxazole were all below the limits of detection of the methods used (between 4 and 20 ng l(-1)). The anti-fungal agent clotrimazole was the most frequently detected at a maximal concentration of 22 ngl(-1) and a median concentration of 7 ngl(-1). The analgesic compound ibuprofen was detected at a maximal concentration of approximately 930 ngl(-1) and a median concentration of 48 ngl(-1), whilst the other pharmaceutical compounds were detected between the limits of detection of the method used and 570 ngl(-1). Crown Copyright (C) 2004 Published by Elsevier Ltd. All rights reserved.