This report describes the findings of a Nordic environmental study. The quaternary ammoniums included are compounds which are used in large volumes in a variety of industrial, health sector and domestic products. The quaternary ammoniums are used to provide antistatic, antibacterial, emulating and other properties in a range of formulations like hair conditioners, cosmetics, in fabric softeners and in cleansing and disinfecting products. Some quaternary ammoniums are poorly degraded and some are highly toxic to aquatic organisms. The samples analysed were taken mainly near assumed hot-spot areas as in sewage lines and in receiving waters, but also in background areas far from anthropogenic sources. Samples include water, sludge, sediment and fish.