Sandimirov S. Screening studies of POP levels in fish from selected lakes in the Paz watercourse / In State of the environment in the Norwegian, Finnish and Russian border area. The Finnish Environment. Finland, Jyvaskyla: Kopijyva Oy. 2007, №6.

Screening studies o f POPs in fish from the Paz watercourse Table 1. Study localities in the Paz watercourse. Lake Stuorajavri is not part o f the Paz watercourse, but it was included in the study as a reference lake. R =Russia, N =Norway. Locality Station number Country Approx. distance from smelters 2004 2005 Aug. Sept. June Sept. Kuetsjarvi 1 R 5 km X Skrukkebukta 2 N 16 km X X Tjsrebukta (Vaggatem) 3 N 40 km X X Ruskebukta (Vaggatem) 4 N 40 km X X Rajakoski 5 R 65 km X Stuorajavri1-1 6 N 290 km X :) Reference lake located in the Kautokeino-Alta watercourse, Norway. 3 Sampling procedure The fieldwork was carried out as in cooperation between the Norwegian College of Fishery Science (NFH), Institute of North Industrial Ecology Problems (INEP), Kola Scientific Centre, Russian Academy of Sciences, Institute of Biology (IB), Karelian Research Centre, Russian Academy of Sciences, and Akvaplan-niva. Fish sampling was performed in the littoral (< 8 m), profundal (> 10 m) and pelagic habitats (0 - 6 m), using gillnets. The gillnets were 40 m long and contained eight sections with different mesh sizes. Each section was 5 meter long. In the pelagic zone, 6 m deep floating nets were used, whereas 1.5 m deep bottom nets were employed in the littoral and profundal zones. The mesh sizes used were 10, 12.5, 15, 18.5, 22, 26, 35 and 45 mm (knot to knot). Additional samples of perch, pike and brown trout were collected using large-sized gillnets (>35 mm mesh size). In all studied lakes, the whitefish is represented by two different morphs, differentiated by their number and morphology of gill rakers and referred to as sparsely rakered (SR) and densely rakered (DR) whitefish (Amundsen et al., 2004). The two whitefish morphs exhibit distinct genetic and ecological differences (Amundsen 1988; Amundsen et al., 2004), and are treated as functional species in the analysis and presentation of the results. After retrieval from sampling devices, each fish was identified to the species level by personnel that are familiar with the taxonomy of the fish in the Pasvik River Basin. The following fish species were collected for contaminant analyses during 2004-2005: whitefish ( Coregonus lavaretus), pike (Esox lucius), perch (Perca fluviatilis) and vendace (Coregonus albula). Each fish was measured for fork length and weight, sex and stage of maturation were recorded, and stomachs samples were collected and preserved in 96 % ethanol for diet analyses. Otoliths were sampled from whitefish and vendace and opercula from perch for age determinations. Dissection of fish and sampling of tissues were carried out with knife, scissors and scalpel made of stainless steel. The tissue samples (muscle and liver, weight 3-10 g) were put into plastic sachets for mercury analysis and in aluminium foil for POP analyses. Samples were stored frozen in the field and transported frozen to the laboratory for analyses. Akvaplan-niva report APN 514-3365.02 6