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Accumulation and transportation of natural radionuclides in estuary

Research Project

Project/Area Number 05680449
Research Category

Grant-in-Aid for General Scientific Research (C)

Allocation TypeSingle-year Grants
Research Field Environmental dynamic analysis
Research InstitutionKYUSHU UNIVERSITY

Principal Investigator

OSAKI Susumu  Kyushu University, Radioisotope Center, Professor, アイソトープ総合センター, 教授 (90037276)

Project Period (FY) 1993 – 1994
Project Status Completed (Fiscal Year 1994)
Budget Amount *help
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1994: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1993: ¥1,100,000 (Direct Cost: ¥1,100,000)
KeywordsNatural radionuclide / Estuary / Transportation / Distribution coefficient / Benthos / Conveyer belt feeding
Research Abstract

Natural atomospheric radio-nuclides, unsupported ^<210>Pb (^<210>Pb minus ^<214>Bi), and ^7Be in three estuarine sediments from Tatara-Umi estuary were measured. Their profiles of the silty sediments from tidal flat are fitted down to 30 cm on a simplest equation for diffusion (mixing) with the coefficients from 1 to 8 x10^<-7> cm^<2s>ec^<-1>. The monthly profiled of ^7Be in tidal flat sediments show no different mixing on season. This mixing is faster than those expected from microcosmic experiments. The upper 7,8 cm of the silty sediments from reed marsh are well mixed, probably owing to the growth of roots of reeds. Under the well mixed layr, ^<210>Pb and ^7Be are decreased with the depth in a similar manner as tidal flat sediments. In seaside sand sediments their nuclides do not absorbed.
The radio-nuclides of ^<22>Na, ^<85>Sr, ^<134>Cs, ^<59>Fe, ^<54>Mn, ^<57>Co and ^<65>Zn had been spiked on untreated or heated estuarine sediments. After 1,2 or 3 months, the profiles of their radio-activities were measured by g-spectrometry simultaneously. In heated samples, Na and Sr are transported down to the bottom of 12cm, Cs down to 3-4 cm, and other elements are hardly transported. In untreated samples, Fe, Mn, Co and Zn are transported down to 4-5 cm and several samples showed peaks, which suggest bioturbation and conveyor-belt deposit feeders. The bioturbation were heterogeneous in time and place in Tatara-Umi estuary. The transfer of these elements can be simulated by an advection-diffusion-reaction model.

Report

(3 results)
  • 1994 Annual Research Report   Final Research Report Summary
  • 1993 Annual Research Report
  • Research Products

    (6 results)

All Other

All Publications (6 results)

  • [Publications] 大崎 進: "Vertical rates of radionuclides in estuarine sediments I.Profiles of natural radionuclides in surface sedimentary layers" J.Environmental Radioactivity. 26(発表予定). (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] 大崎 進: "Vertical rates of radionuclides in estuarine sediments II.Laboratory study on radionuclides spiked on the surface estuarine sediments" J.Environmental Radioactivity. 26(発表予定). (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] S.Osaki: "Vertical rates of radionuclides in estuarine sediments I.Profiles ofnatural radionuclides in surface sedimentary layrs" J.Environmental Radioactivity. 26(In press). (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] S.Osaki: "Verticalrates of radionuclides in estuarine sediments II.Laboratory study on radionuclides spiked on the surface estuarine sediments" J.Environmental Radioactivity. 26(In press9. (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] 大崎 進: "Vertical rates of radionuclides in estuarine sediments I.Profiles of natural radionuclides in surface sedimentry layers" J.Environmental Radioactivity. 26(発表予定). (1995)

    • Related Report
      1994 Annual Research Report
  • [Publications] 大崎 進: "Vertical rates of radionuclides in estuarine sediments II.Laboratory study on radionuclides spiked on the surface estuarine sediments" J.Environmental Radioactivity. 26(発表予定). (1995)

    • Related Report
      1994 Annual Research Report

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Published: 1993-04-01   Modified: 2016-04-21  

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