Environ Monit Assess DOI 10.1007/s10661-008-0730-7 Heavy metals in bottom sediments of Lake Umbozero in Murmansk Region, Russia J. Jernström · J. Lehto · V. A. Dauvalter · A. Hatakka · A. Leskinen · J. Paatero Received: 8 June 2008 / Accepted: 23 December 2008 © Springer Science + Business Media B.V. 2009 Abstract Sediment cores collected from different locations of Lake Umbozero were studied with respect to concentration and mobility of trace and heavy metals Co, Cu, Fe, Mn, Ni, Pb, U, and Zn. Lake Umbozero is the second largest lake in the Murmansk Region and subjected to contamination by air-borne emissions and river transportation from the nearby metallurgical and mining industries. Unlike its neighboring, more J. Jernström (B ) Radiation Research Division, Risoe National Laboratory for Sustainable Energy, Technical University of Denmark—DTU, P.O. Box 49, 4000 Roskilde, Denmark e-mail: jussi.jernstroem@risoe.dk J. Lehto · A. Hatakka · A. Leskinen Laboratory of Radiochemistry, Department of Chemistry, University of Helsinki, P.O. Box 55, 00014 Helsinki, Finland V. A. Dauvalter Institute of North Industrial Ecology Problems (INEP), Kola Science Centre, Russian Academy of Sciences, 14 Fersman St, Apatity, Murmansk Region, 184209, Russia J. Paatero Finnish Meteorological Institute, Arctic Research Programme, P.O. Box 503, 00101 Helsinki, Finland industry-prone Lake Imandra, Lake Umbozero is relatively unexplored with respect to its state of pollution. In our study, metal distribution in sediments was found to vary with respect to the cores, although in general the concentrations were at the same level throughout the lake indicating uniform horizontal distribution of metals. When compared to Lake Imandra, the concentrations of most of the metals studied were significantly lower and represented the levels in sediments measured in lakes of Kola Peninsula located further off from industrial pollutant sources. An exception was Pb the concentration of which was at the same level as in Lake Imandra, probably due to long-distance transport. Sediment layers were subjected to four- step sequential extraction procedure to reveal the metal distribution in soluble, exchangeable, acid- soluble, and residual fractions. Indicative of their potential higher lability, Mn, U, and Zn were generally found in exchangeable fraction; as also Mn and U extensively in the acid-soluble fraction. Keywords Umbozero · Sediments · Pollution · Metals · Extraction · Mobility Introduction Rich mineral sources in the Murmansk Region of the Kola Peninsula, Russia, have given rise to