Sandimirov S. Screening studies of POP levels in bottom sediments 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 of PO P levels in bottom sediments from selected lakes in the P az watercourse All trace element levels decreased with increasing distance from the smelters. According to Norwegian Pollution Control Authorities (SFT) environmental classification (Andersen et al., 1997) o f freshwater sediments, Kuetsjarvi Lake sediments can be considered as “ strongly contaminated” with Cu and Ni, “markedly contaminated” with Hg, and “moderately contaminated” with Cd. The Paz-watercourse sediments can be classified as “markedly contaminated” with Ni and Cu, “moderately contaminated” with Cd, while Hg levels were as low as “background” levels (Andersen et al., 1997). 5.3. Polycyclic aromatic hydrocarbons (PAHs) Polycyclic aromatic hydrocarbons (PAHs) belong to one o f the most hazardous classes of hydrophobic persistent organic pollutants having high potential for accumulation in biological tissues. Recent studies have examined dioxin-like activity o f PAHs and shown that their contribution to total toxicity equivalent value is greater that those by dioxins and dioxin-like polychlorinated biphenyls (Willett et a l, 1997; Clemons e t al., 1998; Klimm et al., 1999; Kannan et al., 2000; Eljarrat et a l, 2001). PAHs are ubiquitous contaminants o f lacustrine sediments which arise from incomplete combustion o f organic matter in flames, engines, and industrial processes (pyrogenic PAHs) and from emissions o f oil-derived products (petrogenic PAHs). PAHs o f biogenic origin are generated by biological processes or by the early stages o f diagenesis in sediments (e.g. perylene) (Venkatesan, 1988). Therefore the level o f perylene is related to the conditions in the catchment area o f the lake. A catchment area with a lot of peat and bogs can lead to high levels o f perylene in the lake sediments. Perylene is therefore often excluded when levels o f PAHs are discussed. The relative amounts o f the less stable kinetic PAH isomers compared to the more stable thermodynamic isomers o f the same molecular mass (PAH ratios) are temperature dependent (Alberty and Reif, 1988) and they can indicate combustion or anthropogenic inputs (Yunker et a l , 1995; 1996). Table 3 summarize the results o f PAH analyses in bottom sediment samples collected in the study area. Geographical distribution o f total PAH concentrations (EPAH) are presented in Figure 4. Rapport APN- 514.3665.01 10