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 PCDD/PCDF levels in muscle and liver of fish from the Paz watercourse and Lake Stuorajavri are presented in Tables 3.7 and 3.8., Appendix 3. The distribution of PCDD/PCDF hepatic levels in fish from the study area is shown in Figure 8. 71 7.4 д Stuorajarvi Kuetsjarvi Pike, liver ■ IPCDD/F, pg/g ww N n.d. tuorajavri 69°L*ke 22°E Bjomevatn NORWAY n.d Skruikkei • \ bukta Pasvik River \ 4 \ о n.d. Svanvikn Salmijarvin Kuetsjarvi Steinbakk □ lake Skogfossn Pasvik River • / Ruskebukta White fish, liver EPCDD/F, pg/g ww F I N L A N D Inarijarvi Lake 24°E 26°E 28°E 30°E Figure 8. Distribution ofPCDD/PCDF hepatic levels infish from the study area 2,3,7,8-TCDD, the most commonly studied chlorinated dioxin was not found in any of the samples from the study area or the reference site. 2,3,7,8-TCDF and OCDD were found in highest concentrations in fish tissue from the study area. Only limited data exists on PCDD/PCDF levels in whitefish and pike from other regions. In 1996, PCDD/PCDF levels were studied in fish from 14 localities along the River Kymijoki and its estuary in Finland. The concentrations were found to be low, in most samples below 1 pg/g Toxicity Equivalents (TEQ) (Korhonen et al., 2001) (se below for explanation of TEQs). The concentrations of PCDD/F in pike muscle ranged from 0.2 to 0.8 pg/g ww TEQ in Finnish coastal areas in 1990 (Korhonen and Vartiainen, 1997) and were somewhat lower (about 0.1 - 0.4 pg/g ww TEQ) in Finnish lakes. The highest PCDD/PCDF levels in pike were detected in Kymijoki River, varying between 0.4 and 1.3 pg/g ww TEQ. Exposure and effects: Of the 210 dioxins and furans, 17 contribute most significantly to the toxicity of complex of mixtures. In order to facilitate a comparison of mixtures, International Toxicity Equivalency Factors (TEQs) have been assigned to individual dioxins and furans based on a comparison of toxicity to 2,3,7,8-tetrachlorodibenzo-p-dioxin or TCDD. The IARC has determined that 2,3,7,8-TCDD can cause human cancer. These compounds are also Akvaplan-niva report APN 514-3365.02 17