Human impact on the transport of terrigenous and anthropogenic elements to peri-alpine lakes Switzerland over the last decadesReport as inadecuate




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Aquatic Sciences

, Volume 75, Issue 3, pp 413–424

First Online: 22 February 2013Received: 22 August 2012Accepted: 06 February 2013DOI: 10.1007-s00027-013-0287-6

Cite this article as: Thevenon, F., Wirth, S.B., Fujak, M. et al. Aquat Sci 2013 75: 413. doi:10.1007-s00027-013-0287-6

Abstract

Terrigenous Sc, Fe, K, Mg, Al, Ti and anthropogenic Pb and Cu element fluxes were measured in a new sediment core from Lake Biel Switzerland and in previously well-documented cores from two upstream lakes Lake Brienz and Lake Thun. These three large peri-alpine lakes are connected by the Aare River, which is the main tributary to the High Rhine River. Major and trace element analysis of the sediment cores by inductively coupled plasma mass spectrometry ICP-MS shows that the site of Lake Brienz receives three times more terrigenous elements than the two other studied sites, given by the role of Lake Brienz as the first major sediment sink located in the foothills of the Alps. Overall, the terrigenous fluxes reconstructed at the three studied sites suggest that the construction of sediment-trapping reservoirs during the twentieth century noticeably decreased the riverine suspended sediment load at a regional scale. In fact, the extensive river damming that occurred in the upstream watershed catchment between ca. 1930 and 1950 and up to 2,300 m a.s.l. and that significantly modified seasonal suspended sediment loads and riverine water discharge patterns to downstream lakes noticeably diminished the long-range transport of fine terrigenous particles by the Aare River. Concerning the transport of anthropogenic pollutants, the lowest lead enrichment factors EFs Pb were measured in the upstream course of the Aare River at the site of Lake Brienz, whereas the metal pollution was highest in downstream Lake Biel, with the maximum values measured between 1940 and 1970 EF Pb > 3. The following recorded regional reduction in aquatic Pb pollution started about 15 years before the actual introduction of unleaded gasoline in 1985. Furthermore, the radiometric dating of the sediment core from Lake Biel identifies three events of hydrological transport of artificial radionuclides released by the nuclear reactor of Mühleberg located at more than 15 km upstream of Lake Biel for the time period 1970–2000.

KeywordsLake sediment Terrigenous flux Trace metals Radionuclides Human impact Electronic supplementary materialThe online version of this article doi:10.1007-s00027-013-0287-6 contains supplementary material, which is available to authorized users.

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Author: Florian Thevenon - Stefanie B. Wirth - Marian Fujak - John Poté - Stéphanie Girardclos

Source: https://link.springer.com/







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