The catchment study (1994-1995) concentrated on eight carefully selected, relatively small (12 to 35 km2) drainage basins located in different geological settings, and at various distances from the pollution point-sources (5-300 km) and from the Barents Sea (40-300 km) (see map). The aim of this study was to shed light on the process and dynamics of element cycling in catchments, and thus to help the interpretation of the regional geochemical mapping results. The main characteristics of the catchments are summarised in the following Table.
-------------------------------------------------------------------------------------------------------- # Name Outlet co- Size Elevatn Ann. Vegetation Bedrock Surface cover, ordinates (km2) (m asl) precip. peculiarities (mm)* -------------------------------------------------------------------------------------------------------- RUSSIA C1 Zapol- 69o27'01"N 19.02 25-373 454 birch forest tundra gneiss till, fluvioglacial, jarniy 31o03'49"E outcrop C2 Monche- 67o50'30"N 22.38 128-507 391 technogenic desert, dacite, andesite, till, prone to gorsk 32o54'48"E birch shrubs tuffs, gabbro/ erosion norite C3 Kirovsk 67o32'50"N 20.01 240-1075 502 spruce forest, nephelinite till, diluvial/ 33o48'55"E mountain tundra eluvial birch forest C4 Kurka 67o41'25"N 20.49 152-466 502 north taiga spruce amphibolite, till, fluvio-glacial 32o50'14"E forest, birch; gneiss incipient deterioration NORWAY C5 Skjell- 69o21'25"N 34.56 80-297 422 north taiga pine andesite, basalt, till, esker bekken 29o27'25"E forest, birch tuffs, 'black shale' FINLAND C6 Kirakka 69o35'12"N 11.86 110-200 386 north taiga pine granite outcrop, till, 28o51'46"E forest moraine ridge C7 Naruska 67o21'44"N 20.16 263-490 513 north taiga spruce gneiss till, peat, outcrop 29o22'05"E forest C8 Pallas 68o09'14"N 24.42 303-500 405 north taiga spruce quartzite till, peat 23o52'50"E forest -------------------------------------------------------------------------------------------------------- *from the closest meteorological station (data from 1994) --------------------------------------------------------------------------------------------------------Catchment 1 (C1) is located near the Zapoljarniy ore roasting plant (see map and industry). C2 is located near the massive non-ferrous ore smetling industry of Monchegorsk, while C4 is located further downwind. C3 is located near the apatite mine of Kirovsk. C5 is located at some distance from the Nikel smelters, in a direction perpendicular to the main wind direction. C6-8 are located far from any major industrial emission source.
The choice of catchment locations thus affords an identification of geochemical signatures representing different industrial processes (ore roasting, ore smelting, mining), different geological provinces, as well as the distance from the sea and point-source emitters.
Within each catchment, several different localities were sampled for different media. These were snow, rain, stream water, organic stream sediment, terrestrial moss, topsoil and podzol profiles. In addition, ground water and overbank sediments were collected in selected catchments. Of all these media, several were monitored throughout the year 1994 (e.g. stream water). Field methods are described in detail in the report by Äyräs & Reimann (1995), and the main results are summarised in the national reports from Russia (Chekushin et al., 1995), Finland (Äyräs, 1995) and Norway (Reimann, 1995), details of which can be found in the publication list.
The following diagram shows the great differences that exist in the nickel (Ni) content of snow in the different catchments.
(Diagram: P. de Caritat)