Sandimirov S. Pollution of the Sediments of the Paz River basin / In State of the environment in the Norwegian, Finnish and Russian border area. The Finnish Environment. Finland, Jyvaskyla: Kopijyva Oy. 2007, №6, 98p.

In regional distribution o f Pb the different patter from all heavy metals is noticed - the increase in concentrations in superficial layers o f sediment o f headwaters o f the Paz River and the lakes removed from the main source o f pollution, suggesting that that the basic sources o f Pb are in Northern Finland and Northeast Norway. Main source Pb, most likely, is use o f gasoline with tetra-ethyl lead in quality o f antiknock component. 1.3.4. Contamination degree of Hakanson The factor and degree o f the heavy metal pollution o f lake sediments with special indices were described by Hakanson (1980) (factor (Cf) and degree (Cd) o f contamination). To evaluate the contamination by heavy metals in the investigated lakes, we have defined a contamination factor (Cf) values according to Hakanson, (1980) as a ratio o f concentrations in a surficial sediment to a background value for a given lake. Contamination degree (Cd) values were defined as the sum of all contamination factors for a given lake. To determine the ecological state o f the investi­ gated lakes, the values of the contamination factor of eight elements (Cu, Ni, Zn, Co, Cd, Pb, Hg, As - the prevailed polluted elements in this region) were calculated. These values are shown in Table and Appendix. The following terminology is suggested for describing the contamination factor (Cf): Cf <1 - low contamination factor; 1< Cf <3 - moderate contamination factor; 3< Cf <6 - considerable contamination factor; Cf >6 - very high contamination factor. The following terminology is adopted to describe the degree o f contamination (Cd-values) for eight substances: Cd<8 - low degree of contamination; 8< Cd <16 - moderate degree o f contamination; 16< Cd <32 - considerable degree o f contamination; Cd>32 - very high degree o f contamination indicating serious anthropogenic pollution. Maximal values o f contamination factor (Cf) o f almost all heavy metals are marked in sediments o f the Kuetsjarvi and lakes (LN-2, LN-3, LN-4, Peschanoe, Palojarvi, Zapoljarny, Kirikovan- jarvi) on distance up to 20 km from the “Pechenganickel” Company. The lake Bjornevatn has very high values o f Cf for Ni and Hg, considerable - Cu, Cd, As, moderate - for others ТМ. Values of Cf for many heavy metals for water areas o f upper and lower watercourse o f the Paz River are on the borderline between low and moderate, with exception Hg and Cd. Practically all researched Norwegian and Finnish lakes have low and moderate values o f Cf for Ni, Cu, Zn, Co. Very high values o f Cf are marked for Pb and As in lakes Isalombola, Sametivatn, Gjekvatn (Norway), Lampi 222, Mellalompolo, Kantojarvi (Finland) and o f some other lakes. Lakes on the distance up to 20 km from the “Pechenganickel” Company and lakes Kuetsjarvi and Bjornevatn have maximal values o f Cd (very high according to the classification o f Hakan­ son). Very high values o f Cd are fixed as well in more removed lakes - Alla-Akkajarvi (45 km, due to very high values of Cf for Ni, Cu, Pb), Isalombola (59 km, very high value o f Cf for Pb), Virtuovoshjaur (90 km, very high value o f Cf for Hg) (Fig. 1). For the most part o f the Finnish lakes the values o f Cd are on borderline between considerable and moderate owing to high val­ ues of Cf for Pb, Cd and As, moderate values o f Cd - for the most part o f the Norwegian lakes are typical. 8