National Environmental Monitoring in Sweden. The monitoring of persistent organic pollutants (POPs) in fish is performed in 110 lakes in Sweden and annual sampling is carried out in 32 lakes, of which 7 are located in or close to the AMAP area. Three fish species have been selected: Arctic char (Salvelinus alpinus), Northern pike (Esox lucius), and Perch (Perca fluviatilis). Fish are sampled, prepared, and stored in the Environmental Specimen Bank (ESB) at the Swedish Museum of Natural History (NRM). PCB, HCH, HCB, DDT, DDE, PFAS and PBDE are some of the POPs that are analysed.