Chemical composition of lake sediments along a pollution gradient in a Subarctic watercourse / Dauvalter V., Kashulin N., Sandimiriv S. [et al.] // Journal of Environmental Science and Health. Part A. - 2011. - Vol. 46. - P. 1020-1033.

Downloaded by [Vladimir Dauvalter] at 21:54 24 November 2013 Journal o f Environmental Science and Health, Part A (2011) 46, 1020-1033 Copyright © Taylor & Francis Group, LLC ISSN: 1093-4529 (Print); 1532-4117 (Online) DOI: 10.1080/10934529.2011.584503_________________________________ Chemical composition of lake sediments along a pollution gradient in a Subarctic watercourse VLAD IM IR DAUVALTER1, NIKOLAY KA SHU L IN 1, SERGEY SANDIM IROV1, PETR TERENT JEV1, DM ITRY DENISOV1 and PER -ARNE AMUNDSEN 2 1 Institute o f North Industrial Ecology Problems (INEP), Kola Science Centre, Russian Academy o f Science, Apatity, Murmansk Region, Russia 2Department o f Aquatic Biosciences, University o f Troms 0 , Troms 0 , Norway Sediment cores were collected from seven lakes in the Subarctic Pasvik watercourse, polluted by sewage waters and air emissions from the Pechenganickel Metallurgical Company, in order to study chemical composition and estimate the intensity of pollution by taking into account background concentration of elements and the vertical and spatial distribution of their contents in cores and surficial layers of sediments. Sediment samples were analysed by atomic-absorption spectrophotometry for 18 elements (Ni, Cu, Co, Zn, Cd, Pb, Hg, As, Cr, Sr, Mn, Fe, Ca, Mg, Na, K, Al, P). Maximum concentrations of all investigated heavy metals (Ni, Cu, Co, Zn, Cd, Pb, Hg, As) were found in the surficial sediment layers of Lake Kuetsjarvi situated directly below the metallurgic smelters. Decreased contents of heavy metals were observed in surficial sediment layers further downstream in the Pasvik watercourse, although pollution remained rather high. Considerable increase in the contents of the heavy metals emitted into the atmosphere in significant amounts by the Pechenganickel Company (Ni, Cu, Co, Zn), was not observed in surficial sediment layers of lakes upstream in the watercourse polluted only by air contamination and household sewage, but substantial increase of the concentrations of chalcophile elements (Pb, Cd, Hg, As) was revealed. The increase in P contents towards the sediment surface in some lakes may suggest a development of eutrophication processes. Our studies reveal that the metallurgic processing of the Pechenganickel Company has resulted in comprehensive heavy metal pollution and contaminations of lakes sediments in the Inari-Pasvik watercourse. The pollution impact on the sediments is most severe in Lake Kuetsjarvi in the vicinity of the smelters, intermediate in lake localities in the main watercourse downstream the metallurgic enterprises and least in lake localities in the upstream part of the watercourse. Keywords: Subarctic watercourse, lake sediments, heavy metals, degree of contamination. Introduction A tmospheric emissions and sewage runo ff o f contam inants from mining activity and metallurgic industry is a source of serious environmental pollution for many freshwater sys­ tems. Lakes and reservoirs and their sediments serve as col­ lectors o f all substances entering their catchments, and lake sediments thus accumulate data about the flow o f elements in an historical perspective. The sediments are therefore an important source o f information bo th for the present and historical climatic, geochemical and ecological condi­ tions o f the lake and its catchment. The concentrations of pollutants in the sediments allow an assessment o f the in­ tensity and history o f pollution o f the investigated lakes, and lake sediments are accordingly considered to be good Address correspondence to Vladimir Dauvalter, Institute of North Industrial Ecology Problems (INEP), Kola Science Centre, Russian Academy of Science, 184209, Fersman St., 14a, Apatity, Murmansk Region, Russia; E-mail: vladimir@inep.ksc.ru Received December 3, 2010. indicators o f e.g., heavy metal pollution.[1-4] Regional anal­ yses o f contam ination levels in the surficial sediments o f lakes provide information about the spatial distribution o f pollutants.[5-8] The historical development o f pollution im­ pacts on specific lake systems can furthermore be explored by examination o f contam inant concentrations at differ­ ent depths o f sediment core samples.[8-12] Hence, sediment analyses constitute a very useful tool for studying pollution impacts on freshwater systems. The drainage network o f the Inari-Pasvik watercourse forms the largest water system in the No rthern p art o f Fennoscandia (Fig. 1). Its catchment area is located in the border region between Russia, Norway and Finland. The emissions o f heavy metals, sulphurous gas, alkaline and alkaline earth metals, and dust from the smelters o f the Pechenganickel Company located in the lower p a rt o f the watercourse, represent a large anthropogenic influence on terrestrial and water ecosystems in the region. A tmo ­ spheric emissions and sewage runo ff from smelters, tailing dams and slag piles from this metallurgic industry is the main source o f pollution o f the Inari-Pasvik watershed.