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Density-driven displacement of pore water as possible factor affecting the vertical distribution of Chernobyl-derived radionuclides in a Baltic Sea sediment

Abstract

The vertical distribution of radionuclides in the bottom sediment of Gaevle Bay, southern Bothnian Sea, was investigated after the Chernobyl fallout. Sediment cores collected two years after the initial fallout revealed the highest radionuclide concentrations found in the Baltic Sea, reflecting the heavy fallout over this region. Concentrations of nuclides were almost constant down to about 8 cm sediment depth. Results from calculations by solving the one-dimensional diffusion equation were compared with the measured concentrations of radionuclide. The computed values were much lower than the observed ones, and diffusion alone could not account for the distribution pattern in the sediment. The macrobenthic community was scarce and vertical mixing of pore water could not be explained by bioturbation either. Vertical displacement of the pore water, caused by changes in density of the overlying water column, is a possible mechanism which could explain the rapid penetration of fallout nuclides in the soft bottom sediment. 8 refs, 16 figs, 3 tabs.
Authors:
Publication Date:
Jun 07, 1994
Product Type:
Technical Report
Report Number:
STUDSVIK-ES-94-32
Reference Number:
SCA: 540330; PA: AIX-26:010291; EDB-95:031411; SN: 95001323661
Resource Relation:
Other Information: PBD: 7 Jun 1994
Subject:
54 ENVIRONMENTAL SCIENCES; SEDIMENTS; RADIONUCLIDE MIGRATION; BALTIC SEA; PORE PRESSURE; RADIOACTIVITY; SPATIAL DISTRIBUTION; WATER; 540330; RADIOACTIVE MATERIALS MONITORING AND TRANSPORT
OSTI ID:
10111309
Research Organizations:
Studsvik Eco and Safety AB, Nykoeping (Sweden)
Country of Origin:
Sweden
Language:
English
Other Identifying Numbers:
Other: ON: DE95612428; CNN: Project SSI-P-487.88; ISBN 91-7010-254-6; TRN: SE9400193010291
Availability:
OSTI; NTIS; INIS
Submitting Site:
SWDN
Size:
27 p.
Announcement Date:
Jun 30, 2005

Citation Formats

Evans, S, and Holby, O. Density-driven displacement of pore water as possible factor affecting the vertical distribution of Chernobyl-derived radionuclides in a Baltic Sea sediment. Sweden: N. p., 1994. Web.
Evans, S, & Holby, O. Density-driven displacement of pore water as possible factor affecting the vertical distribution of Chernobyl-derived radionuclides in a Baltic Sea sediment. Sweden.
Evans, S, and Holby, O. 1994. "Density-driven displacement of pore water as possible factor affecting the vertical distribution of Chernobyl-derived radionuclides in a Baltic Sea sediment." Sweden.
@misc{etde_10111309,
title = {Density-driven displacement of pore water as possible factor affecting the vertical distribution of Chernobyl-derived radionuclides in a Baltic Sea sediment}
author = {Evans, S, and Holby, O}
abstractNote = {The vertical distribution of radionuclides in the bottom sediment of Gaevle Bay, southern Bothnian Sea, was investigated after the Chernobyl fallout. Sediment cores collected two years after the initial fallout revealed the highest radionuclide concentrations found in the Baltic Sea, reflecting the heavy fallout over this region. Concentrations of nuclides were almost constant down to about 8 cm sediment depth. Results from calculations by solving the one-dimensional diffusion equation were compared with the measured concentrations of radionuclide. The computed values were much lower than the observed ones, and diffusion alone could not account for the distribution pattern in the sediment. The macrobenthic community was scarce and vertical mixing of pore water could not be explained by bioturbation either. Vertical displacement of the pore water, caused by changes in density of the overlying water column, is a possible mechanism which could explain the rapid penetration of fallout nuclides in the soft bottom sediment. 8 refs, 16 figs, 3 tabs.}
place = {Sweden}
year = {1994}
month = {Jun}
}