<abstract xml:lang="en" xmlns="http://www.w3.org/1999/xhtml"><p>The biggest problem with most lakes that have no contact with other water sources and are being charged by precipitation is the massive eutrophication. The aim of this work was to determine the sedimentation rate in order to evaluate the progress of eutrophication for St. Ana Lake (Ciomad Mountain near the Băile Tuşnad in Harghita County (Romania)). The concentration of 210Pb was determined by means of high resolution gamma spectrometry as well as derived from 210Po activity which was measured through alpha spectrometry; values obtained are in good agreement. For the excess 210Pb activity values between 4.0±0.5 Bq/kg and 218±20 Bq/kg have been found. As an alternative method, the 137Cs dating method was applied as well. Calculated mass sedimentation rates are in the range of 0.06±0.01 to 0.32±0.05 g/cm2 year with a mean of value of 0.15±0.02 g/cm2 year. Linear sedimentation rates yielded much higher sedimentation values (between 0.5±0.1 and 7.9±0.7 cm/year with a mean of 2.4±0.6 cm/year), due to the predominant organic matter composition and the long suspension time of the sediment. This is an indication for the process of eutrophication which will probably lead to the transformation of the lake into a peat bog.</p></abstract>

The biggest problem with most lakes that have no contact with other water sources and are being charged by precipitation is the massive eutrophication. The aim of this work was to determine the sedimentation rate in order to evaluate the progress of eutrophication for St. Ana Lake (Ciomad Mountain near the Băile Tuşnad in Harghita County (Romania)). The concentration of 210Pb was determined by means of high resolution gamma spectrometry as well as derived from 210Po activity which was measured through alpha spectrometry; values obtained are in good agreement. For the excess 210Pb activity values between 4.0±0.5 Bq/kg and 218±20 Bq/kg have been found. As an alternative method, the 137Cs dating method was applied as well. Calculated mass sedimentation rates are in the range of 0.06±0.01 to 0.32±0.05 g/cm2 year with a mean of value of 0.15±0.02 g/cm2 year. Linear sedimentation rates yielded much higher sedimentation values (between 0.5±0.1 and 7.9±0.7 cm/year with a mean of 2.4±0.6 cm/year), due to the predominant organic matter composition and the long suspension time of the sediment. This is an indication for the process of eutrophication which will probably lead to the transformation of the lake into a peat bog.

A sedimentation study of St. Ana Lake (Romania) applying the 210Pb and 137Cs dating methods

Faculty of Environmental Science, Babes-Bolyai Universityc, 400294, Cluj Napoca, Fantanele nr. 30, Romania

Department of Radiochemistry, University of Pannonia, 8200, Veszprén, Egyetem nr. 10, Hungary

Geochronometria

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

The biggest problem with most lakes that have no contact with other water sources and are being charged by precipitation is the massive eutrophication. The aim...

A sedimentation study of St. Ana Lake (Romania) applying the 210Pb and 137Cs dating methods

Publié en ligne: 20 mars 2011

Pages: 93 - 100

DOI: https://doi.org/10.2478/s13386-011-0017-6

Mots clés
210Pb dating, alpha spectrometry, gamma spectrometry, 137Cs, sedimentation rate

© 2011 Silesian University of Technology, Gliwice, Poland

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

A sedimentation study of St. Ana Lake (Romania) applying the 210Pb and 137Cs dating methods

Publié en ligne: 20 mars 2011

Pages: 93 - 100

DOI: https://doi.org/10.2478/s13386-011-0017-6

Mots clés210Pb dating, alpha spectrometry, gamma spectrometry, 137Cs, sedimentation rate

© 2011 Silesian University of Technology, Gliwice, Poland

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Mots clés
210Pb dating, alpha spectrometry, gamma spectrometry, 137Cs, sedimentation rate