Thanks to Unni Mette Nordang (NILU) for packaging and shipping of the sample bottles. Fredrik Andreasson (Länsstyrelsen i Blekinge län, Sverige) and Kristin Galtung (NIVA) for sampling, in addition to all the local participants in the Nordic countries. We thank the City of Lahti for providing assistance in sampling and Halla W. Reinert for helping with the sampling on the Faroe Islands.