Kein Folientitel

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Radon in Urban Areas
Jens Wiegand Würzburg University
19 May 2005
Jens Wiegand
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Radon
natürlich vorkommendes Edelgas, radioaktiv, mit
Hwz. 3,8 Tage
4,5?109 a
U-238
Th-234
Pa-234
24,1 d
1,18 min
U-234
Th-230
Ra-226
Rn-222
Po-218
Pb-214
3,1 min
Bi-214
27 min
245?103 a
75?103 a
1,6?103 a
3,83 d
Po-214
Pb-210
20 min
?- Strahler
Mutter- Nuklid
Bi-210
22,3 a
164?10-6 s
?- Strahler
Stabiles Isotop
Po-210
Pb-206
5,0 d
138 d
19 May 2005
Jens Wiegand
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Why to work as a scientist about radon?
Radon is dangerous.see later To use radon as a
tool to identify geogenic processes
?
?
Radon
?
?
?
19 May 2005
Jens Wiegand
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Wolfango Plastino et al. Very precise monitoring
since 1996 (Rn, pH, EC, TDGP, T) Jens Wiegand et
al. ½ h monitoring since 2003 (Rn, T), and from
now on additionally CO2, EC, TDGP)
W. Plastino, R. Di Giovambattista, P. G.
Catalano, F. Bella, Chemical-physical groundwater
anomalies related to seismic events in central
Apennines (Italy), Earth and Planetary Science
Letters, submitted.
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Thoron
19 May 2005
Jens Wiegand
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Radon is the second most cause of lung cancer
(smoking is the first)
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Folgen der Strahlenexposition
7 of German lung cancer are due to radon(2500
- 3000 cases / year) Lung cancer risk increases
with 10 per 100 Bq/m³ EPA assumes that approx.
20 000 people die due to radon every year
19 May 2005
Jens Wiegand
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Regulation in Germany
Working place action level 2 MBq x h/m³ (6
mSv/a, 1000 Bq/m³) limit value 6 MBq x h/m³
(20 mSv/a, 3000 Bq/m³) At home Rn-Protection
-Law under preparation aim value 100 Bq/m³
19 May 2005
Jens Wiegand
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Why to work as a geoscientist about radon?
Radonexposition in dwellings Radon comes to 95
from the geological bedrock Building material
and drinking water only 5
19 May 2005
Jens Wiegand
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• good knowledge about the geogenic soil radon
  potential
• many measurements under undisturbed soil
  conditions

• but
• only every 3 km 1 measuring point
• what parameter
• additionally to geology?

Würzburg
19 May 2005
Jens Wiegand
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Is it possible to transfer the results into the
cities?
?
Measurements only in rural areas
Measurements in urban areas under consideration
of anthropogenic parameters still missing
19 May 2005
Jens Wiegand
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The 10 Point System
Identification and evaluation of processes
controlling the soil radon potential
19 May 2005
Jens Wiegand
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Radon migration in the soil
Radon Exhalation (transfer from soil to
atmosphere)
Diffusion (by concentration gradient)
Convection (by pressure differences)
Radium Radon
Radium Radon
Radon Emanation (entry into pores)
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• Radon emanation controlled by
• Radium concentration
• Radium distribution in the mineral grains

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Radon emanation processes
(Wiegand 2001)
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The 10 point system
Identification and evaluation of processes
controlling the soil radon potential - 7
parameters identified - Semi-quantitative
evaluation - Ranked according to importance -
Score between 0 and 10
19 May 2005
Jens Wiegand
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Definition of soil radon potential
A qualitative and semi quantitative
evaluation of - Radon concentration in
soil-gas - Radon availability (possibility to
migrate), i.e. permeability
19 May 2005
Jens Wiegand
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7 Parameter of soil radon potential
1. Occurrence of backfill 2. Geology 3. Relief
(variety of soils) 4. Vegetation 5. Tectonics
(faults) 6. Soil sealing 7. Traffic vibrations
19 May 2005
Jens Wiegand
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Occurrence of made ground
222Rn conc. of soil-gas Bq/l 222Rn exhalationrateBq/(m2h)
median of made ground 9 (217) 31 (28)
median of undisturbed soil 43 (307) 61
value from NCRP (1988)
(Wiegand 2001)
19 May 2005
Jens Wiegand
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Geology



(Wiegand 1996)
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Geology



(Wiegand Büchel 1997)
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Relief (variety of soils)



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Relief (variety of soils)



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Relief ( Einfluss der Böden)
Relief (variety of soils)






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Relief (variety of soils)






(Wiegand 2001)
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Relief (variety of soils)






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Relief (variety of soils)






(Wiegand 2001)
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Vegetation






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Vegetation






(Wiegand Feige 1999)
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Tectonics (natural faults)






(Wiegand Büchel 1997)
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Tectonics (man made faults)






(Wiegand 2001)
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Soil sealing
(Wiegand 2000)
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Soil sealing
(Wiegand 2003)
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Traffic Vibrations
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Traffic Vibrations






(Wiegand 2003)
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Traffic Vibrations (The model)



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Traffic Vibrations (The model)



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The 10 point system
Score 7
House granite, plain, fields, railway track
(Wiegand 2001)
19 May 2005
Jens Wiegand
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The 10 point system



(Wiegand in press)
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The 10 point system



(Wiegand in press)
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Application of the 10-ps

• Estimation of soil radon potential
• Estimation of radon conc. in soil-gas
• Estimation of indoor radon (if the radon source
  is the soil and not the building material)
• Verification of the local radon risk in radon
  prone areas
• Support of measurements (indoor radon or
  soil-gas)

19 May 2005
Jens Wiegand
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Advantage of the 10 PS

• Applicable at any site on a local scale
• Application is independent of season
• Evaluation of parameters were done under
  standardised conditions
• (No need of further measurements)

19 May 2005
Jens Wiegand
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Thank you for your attention !
Verena Husmann
Sebastian Feige
Simone Schmid
Bernd Schott
Simone Tulke
Amir Yousseff
Helga Westerhuis
Dieter Bleile
19 May 2005
Jens Wiegand
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Vegetation
Vegetation






LAK Light-Application- chamber (n)
Volume
(Feige Wiegand in prep.)
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Vegetation
Vegetation






(Feige Wiegand in prep.)
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Vegetation






(Kemski et al. 1996)
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