This volume contains oral papers and posters presented at the "Fifth European Symposium on Organic Micropollutants in the Aquatic Environment" held in Rome (Italy) from 20 to 22 October 1987. The Symposium was organ­ ised within the framework of the Concerted Action COST 641*) which is in­ cluded in the Fourth R&D, Programme on the Environment of the Commission of the European Communities. As for the previous symposia, the aim was to review current studies and technical progress in the area of organic micropollutants in the aquatic environment, particularly since the last symposium held in Vienna in October 1985. The programme consisted of review papers and posters re­ lated to analytical methodologies, transport and transformation of or­ ganic micropollutants in water, water treatment processes and mathemat­ ical modelling. Special sessions were devoted to laboratory data treat­ ment and environmental scenarios. These proceedings provide a good overview of the activities in this fieiu in Europe and constitute a valuable contribution to the understanding and solution of the problems posed by organic micropollutants in the aquatic environment. The Commission of the European Communities wishes to express sincere thanks to the co-organizers of the Symosium, in particular to Mr A. Liberatori and T. La Noce of the Consiglio Nazionale delle Ricerche, Istituto di Ricerca sulle Acque, Rome.