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.

4. Pollution of the Sediments of the Norwegian Lakes of the Paz River basin During two field expeditions (September, 2004 and June-July 2005) fourteen Norwegian Lakes of the Paz River basin (Isalombola, Gjekvatn, Sametivatn, Skrukkevatn, lake N-254, Langvatn, Kobbholmsvatn, Holmvatn, Gardsjoen, Ellentja, Suopatjavre, Stuorajavre-1, Stuorajavre-2, Biggejavre) have been investigated to study chemical composition o f sediment cores and assess the pollution o f water ecosystems. 4.1. Background Concentrations The maximum background concentrations o f heavy metals recorded in the Lakes Gjekvatn (Cu, Zn, Hg), Langvant (Cd), Kobholmsvatn (Ni, Co, Pb), Stuorajavre (As) o f the Paz River basin result from the geochemical and morphometric features o f the lake and its drainage basin (Table 7). The background concentrations o f Cu, Ni, Zn, Co, Cd, Pb, As and Hg in the abovementioned lakes were established to be higher than those in other lakes (Isalombola, Skrukkevatn, Gards­ joen, etc.) by a factor o f 1.5-5 in average. The average background concentrations o f some heavy metals (Ni, Zn, Pb, Hg) in the Norwegian Lakes of the Paz System are approximately equal to those in the small lakes o f the Northern Norway and Kola Peninsula (Rognerud, Fjeld, 1990; Dauvalter, 2000). The average background concentrations o f Cu and Co in the Norwegian investigated Lakes in 2 times higher than those in the small lakes o f the Kola Peninsula, Cd - in 4 times smaller. Table 7. Background concentrations o f heavy metals and As (^g/g, dry weight) in sediment cores o f the investigated Norwegian lakes Lake Layers, cm /g C g i /g N g/ n /g N ^ o /g О ^ d /g о b /g P g As ^g/g Hg ^g/g Isalombola 22 23 80 13 93 6.7 0.09 1.1 1.02 0.090 Gjekvatn 21 22 151 36 236 25 0.33 8.0 0.07 0.168 Sametivatn 18 19 133 39 153 14 0.19 2.4 0.11 0.080 Skrukkevatn 14 15 88 44 138 21 0.16 6.7 1.97 0.035 lake N-254 6 7 28 36 45 7 0.33 1.63 0.93 0.025 Langvatn 13 14 137 31 109 24 0.50 20 3.53 0.056 Kobbholmsvatn 14 15 130 60 197 61 0.22 33.5 1.53 0.037 Holmvatn 12 13 67 20 59 13 0.08 21.9 3.94 0.035 Gardsjoen 16 17 41 28 81 25 0.23 3.1 0.94 0.056 Ellentja 22 23 51 32 123 9.5 0.14 3.5 2.80 0.051 Suopatjavre 17 18 17 22 61 19.3 0.11 4.8 1.77 0.018 Stuorajavre-1 24 25 73 43 51 34.8 0.14 4.4 3.14 0.055 Stuorajavre-2 22 23 68 43 79 25.5 0.08 11.5 6.46 0.064 Biggejavre 25 26 88 35 79 35.1 0.17 1.8 6.63 0.070 Average Min Max Standard deviation 82 17 151 42 34 13 60 12 107 45 236 57 23.0 6.7 61 14.2 0.20 0.08 0.50 0.12 8.9 1.1 33.5 9.7 2.49 0.07 6.63 2.09 0.060 0.018 0.168 0.037 27