Lake water geochemistry on the western Kola Peninsula, north-west Russia

Water samples were taken from 120 lakes spread over the western half of the Kola Peninsula, NW Russia. The samples were analysed for 37 elements, pH and electrical conductivity. Lake water chemistry appears in most cases to be dominated by a Ca/Na–HCO3 signature, characteristic of natural carbonate/silicate weathering. Input of elements from marine derived salts and from the Ni industry (roasting plant at Zapoljarnij, smelter at Nikel and smelter/refinery at Monchegorsk) emissions are restricted to limited regions. Considering that 3 of the worldʹs largest point source emitters of SO2 are located within the area, the median lake water pH is surprisingly close to neutral (6.6, range 4.2–7.4). Indeed some of the apparently SO4 contaminated lakes nearest to the smelters yield the highest pH values. Changes in climate and vegetation from north to south within the survey area probably have an influence on element concentrations and pH as observed in the lake waters. Proton displacement by sea salt cation input provides an explanation of low pH lakes in coastal areas.