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 Paz watercourse areas was similar (Figure 8). For identification o f PCB contamination source in the Lake Inari area more detailed studies are needed. The levels o f PCB in the Paz watercourse are high compared to levels found in surface sediments from other lakes in Northern Norway. Skotvold et al. (1997) investigated 24 different lakes and detected levels from <1.0 ng/g dw - 14 ng/g dw o f I 7PCB in surface sediments. The levels of PCB in sediments from 5 lakes in in the municipality o f Sor-Varanger were higher (>5 ng/g dw) compared to the levels from 10 other lakes in Finnmark County (<3 ng/g dw). The Norwegian Pollution Authorities have not developed an environmental classification system for pollutants in freshwater sediments other than for heavy metals. However the classification system made for marine sediments (Mo lv^r et al., 1997) is sometimes used for freshwater sediments (Rognerud et al., 1997). According to this system the PCB levels measured in the Paz watercourse and the reference lakes are classified as either “Moderately contaminated” (5-25 ng/g dw) or “Markedly contaminated” (25 - 100 ng/g dw). m 18 Figure 8. PCB patterns on sediment samples from Kuetsajarvi and Inarijarvi lakes. PCBs with valid concentrations are shown only. Concentrations o f sum o f non-ortho and mono-ortho substituted PCBs (planar PCBs) ranged from 1.48 ng/g dw (station 3) to 0.14 ng/g dw (station 7). PCBs #118, 105 and 114 were the most abundant planar PCB. Their contributions to sum o f planar PCBs were 42%, 24%, and 21% respectively. Rapport APN- 514.3665.01 19