Sandimirov S.S. Catalogue of lakes in the Russian, Finnish and Norwegian Border Area. Finland, Jyvaskyla: Kopijyva Oy, 2008.

Fig. 45. Vertical distribution of the concentrations of Zn, Co and Cd (цд/д, dry weight) in the sediment core of Lake Holmvatn. 2.6.3. Hydrobiology investigations No direct hydrobiological investigations have been carried out in this lake. 2.7. LAKE ISALOMBOLA Lake Isalombola (watershed of the River Paz) is located 62 km to the south-west of the town of Nickel. The elongated, oval-shaped lake is not large (the area of the lake is 1.62 km2) nor deep (maxi­ mum depth 11 m), and is of glacial ori­ gin.The maximum length is 2.65 km and maximum width 1.07 km. The points of maximum depth are located in the cen­ tral part of the lake. The lake forms part of the Ellenel- va lake-river system. According to the landscape type, the watershed belongs to the forest zone with heights of up to 260 m. The lake shores are low, and covered by shrub vegetation and pine forests. Boulder beds occur in almost parts of the littoral zone. 2.7.1. Hydrochemistry The pH of the water in the lake is close to neutral, and the lake has a low total miner­ alization (average 14.6 mg/l) and alkalinity (average 109 peq/1). During flood periods the pH drops slightly, i.e. oxidation processes do not develop due to the buffering capacity of the water. The lake has low concentrations of base cations and anions, with calcium (average 1.71mg/l) and bicarbonate (average 6.7 mg/l) predominating. The annual chemical cycle of the lake is characterized by a slight reduction in the oxidizability and pH of the water during flood periods when the amount of precipita- Physico-geographical characteristics Watershed River Ellenelva— River Paz (Tjerebukta) Latitude 69°09.493' Longitude 28°58.080' Height above sea level, m 112.0 Maximum length, km 2.65 Maximum width, km 1.07 Maximum depth, m 11 Area, km 2 1.62 Watershed area, km 2 74.0 Study period 2002-2005 Catalogue o f Lakes in the Russian, Finnish and Norwegian BorderArea 89