Within the screening program of 2006 SWECO has had the assignment from theSwedish Environmental Protection Agency to measure the occurrence of WFDpriority Substances in limnic and coastal surface waters of Sweden. Measurementswere made at 95 locations in whole water samples, filtered water samplesand using passive sampling techniques which measures the free (non associated)concentrations. The data set represented a large number of aquatic sites over abroad geographical range (1800 km) in different surface water matrices whichmade the data set ideal for further evaluations of both the co-occurrence of prioritysubstances as well as the occurrence in different water matrices.