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 5.4.3. Toxaphenes The complex mixtures o f polychlorobornanes and camphenes known as toxaphene were widely used in the USA on cotton crops. Similar products have been, and may continue to be used in Mexico, Central America, eastern Europe, and the former Soviet Union (de March et al., 1998). Toxaphene is extremely persistent in soils following pest control application, with reported halv- lives ranging from one to 14 years (Howard, 1991). Data on toxaphene levels in sediments from the study area are presented in Table 6. Table 6. Selected toxaphene congeners (Parlar et al., 1995) and sum o f hexa-, hepta-, octa- and nona/deca-chlorobornane toxaphenes (ng/g dry w eigh t)in bottom sediments. Toxaphenes Station number and sediment slice 1 2 3 6 7 4 5 8a 8b 9a 9b Kuets­ jarvi Kuets­ jarvi Kuets­ jarvi Skrukke' bukta - Bj0rn- vatn Ruske- bukta Tj^re- bukta Lake Inari Lake Inari Lake Stuora- javri Lake Stuora- javri 0-1 cm 0-1cm 0-1 cm 0-1 cm 0-1 cm 0-1 cm 0-1 cm 0-1 cm 15-18cm 0-1 cm 22-23cm Parlar#26 n.d. n.d. n.d. n.d. n.d. n.a. n.a. n.d. n.d. n.d. n.d. Parlar#50 n.d. n.d. n.d. n.d. n.d. n.a. n.a. n.d. n.d. n.d. n.d. Parlar#62 n.d. n.d. n.d. n.d. n.d. n.a. n.a. n.d. n.d. n.d. n.d. Hexa-toxaphene n.a. n.a. n.a. n.a. n.a. 4.39 3.18 n.a. n.a. n.a. n.a. Hepta-toxaphene n.a. n.a. n.a. n.a. n.a. 2.03 2.12 n.a. n.a. n.a. n.a. Octa-toxaphene n.a. n.a. n.a. n.a. n.a. 1.02 0.06 n.a. n.a. n.a. n.a. Nona/deca-toxaphene n.a. n.a. n.a. n.a. n.a. 0.02 0.01 n.a. n.a. n.a. n.a. EToxaphene n.a. n.a. n.a. n.a. n.a. 7.46 5.37 n.a. n.a. n.a. n.a. n.d.=not detected; n.a.=not analysed. Single congeners were not detected in any o f the analysed samples. Analyses o f hexa-, hepta- octa- and nona/deca-toxaphanes were carried out on sediments from two sites only (stations 4 and 5). Total toxaphene concentrations (as a sum o f hexa-, hepta- octa- and nona/deca­ toxaphanes) in sediment samples from these sites were 5.37 and 7.46 ng/g dw respectively (Table 7.) 5.4.4. Polybrominated diphenyl ethers (PBDEs) Polybrominated diphenyl ethers (PBDEs) are commonly used as flame retardants in a variety of applications such as foams, textiles and computer materials. Most industrially manufactured PBDEs contain mixtures of brominated diphenyl ethers. There are 209 possible PBDE congeners and positions of the bromine atoms on the two phenyl rings. There is evidence that some PBDEs bioaccumulate and exert toxic effects at low levels. EPA has classified decabromodiphenyl ether as a possible human carcinogen. PBDEs are also endocrine disrupters. Some resemble the thyroid hormone thyroxin and others are estrogenic. More information on PBDEs can be found in Rahman et al. (2000), de Wit (2002) , de Wit & Muir (2004) and in the special issue o f a Journal o f Environmental Science, Risk & Health (“The State o f Science and Trends o f BFRs in the Environment” v. 29, 2003). Table 7 present the PBDE concentrations (Sum o f 7 congeners) found in sediment samples. Geographical distribution o f the sum o f these contaminants is shown in Figure 9. Rapport APN- 514.3665.01 20