radon in urban areas
DESCRIPTION
Radon in Urban Areas. Jens Wiegand Würzburg University. 19 May 2005. Jens Wiegand. Radon. natürlich vorkommendes Edelgas, radioaktiv, mit Hwz.: 3,8 Tage. 4,5 10 9 a. Th-234. U-238. Pa-234. 24,1 d. 1,18 min. Pb-214. Po-218. Rn-222. Ra-226. Th-230. U-234. 3,1 min. Bi-214. - PowerPoint PPT PresentationTRANSCRIPT
Radon in Urban Areas
Jens Wiegand
Würzburg University
19 May 2005 Jens Wiegand
natürlich vorkommendes Edelgas,radioaktiv, mit Hwz.: 3,8 Tage U-238Th-234
U-234
Pa-234
Th-230Ra-226Rn-222Po-218
Po-214
Pb-214
Bi-214
Pb-210
Bi-210
Po-210Pb-206
-Strahler
-Strahler
4,5109 a
24,1 d
1,18 min
245103 a75103 a1,6103 a3,83 d
3,1 min
27 min
20 min
16410-6 s22,3 a
5,0 d
138 d
Mutter-Nuklid
StabilesIsotop
Radon
Jens Wiegand19 May 2005
Why to work as a scientist about radon?
Jens Wiegand
Radon is dangerous…….see later
To use radon as a tool to identify geogenic processes
19 May 2005
Radon
?? ?
? ?
W. Plastino, R. Di Giovambattista, P. G. Catalano, F. Bella, W. Plastino, R. Di Giovambattista, P. G. Catalano, F. Bella, Chemical-physical Chemical-physical ggroundwater anomalies related to seismic events in central Apennines (Italy)roundwater anomalies related to seismic events in central Apennines (Italy), Earth and , Earth and Planetary Science Letters, submittedPlanetary Science Letters, submitted..
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)
Jens Wiegand19 May 2005
Thoron
Radon is the second most cause of lung cancer (smoking is the first)
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
Jens Wiegand19 May 2005
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 preparationaim value 100 Bq/m³
Jens Wiegand19 May 2005
Why to work as a geoscientist about radon?
Jens Wiegand
Radonexposition in dwellings
Radon comes to 95 % from the geological bedrock
Building material and drinking water only 5 %
19 May 2005
Jens Wiegand
- good knowledge about the geogenic soil radon potential
- many measurements under undisturbed soil conditions
19 May 2005
Würzburg but:- only every 3 km 1 measuring point- what parameter additionally to geology?
Is it possible to transfer the results into the cities?
Jens Wiegand
Measurements only in rural areas
Measurements in urban areas under consideration of anthropogenic parameters still missing
?
19 May 2005
Jens Wiegand
The 10 Point System
Identification and evaluation of processes controlling the soil radon potential
19 May 2005
Radium Radon
Radon Emanation(entry into pores)
Radon Exhalation(transfer from soil to atmosphere)
Convection (bypressure differences)
Diffusion (by concentration gradient)
Radon migration in the soil
Radium Radon
Radon emanation controlled by:- Radium concentration- Radium distribution in the mineral grains
water
decaying Ra-atom
Rn-atom
-partic le
*o
pores w ith - w ithou t adsorption w a te r
o*
o *m ineral grain
o*
o*
o*
o*
Radon emanation processes
(Wiegand 2001)
Jens Wiegand
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
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
7 Parameter of soil radon potential
1. Occurrence of backfill2. Geology3. Relief (variety of soils)4. Vegetation5. Tectonics (faults)6. Soil sealing7. Traffic vibrations
19 May 2005
Jens Wiegand
Occurrence of made ground
222Rn conc. of soil-gas [Bq/l]
222Rn exhalationrate
[Bq/(m2*h)]
median of made ground
9 (217) 31 (28)
median of undisturbed soil
43 (307) 61*
* value from NCRP (1988)
19 May 2005
(Wiegand 2001)
SN
222Rn[Bq /l]
0
100
200
Alum sha le
M a rlsto ne , c la y sc hist
Lim e sto ne , m a rlsto ne
0
200 [m ]
200 m
180
150
120
[m ]
7501110
(Wiegand 1996)
Geology
N ESW
0 [m ]100 200 [m ]
60
222R n[Bq/l]
O D L[nSv/h ]
20
0 0
40 50
10040
80B oundary o f m orainefrom geo logical m ap
M ora ine deposits
U pper C arbonife rous sed im ents
(Wiegand & Büchel 1997)
Geology
S N
160
150
0
[m ]
100 200
222Rn 30
[B q/l]
10
20
40Summer
Relief (variety of soils)
S N
160
150
0
[m ]
100 200
222Rn 30
[B q/l]
10
20
40Winter
Relief (variety of soils)
Relief (= Einfluss der Böden)
S N
160
150
0
[m ]
100 200
222Rn 30
[B q/l]
10
20
40Summer
Relief (variety of soils)
foot of the hill
0
10
20
30
40
50
60
J FMAMJ J ASOND J FMAMJ J ASOND J FMAexh
alat
ion
rat
e [B
q/(
m²*
h)]
82 89
1996 1997
Relief (variety of soils)
(Wiegand 2001)
S N
160
150
0
[m ]
100 200
222Rn 30
[B q/l]
10
20
40Winter
Relief (variety of soils)
top of the hill
0
400
800
1200
1600
J FMAMJ J ASOND J FMAMJ J ASOND J FMAexh
alat
ion
rat
e [B
q/(
m2 *h
)]
1996 1997
Relief (variety of soils)
(Wiegand 2001)
0,0
1,0
2,0
3,0
4,0
5,0
6,0
7,0
0 5 10 15 20
Distance to tree [m]
Rn
-222
co
nce
ntr
atio
n [
Bq
/ l]
Rn
Rn
Vegetation
0
5
10
15
20
25
Permeability *10exp-12 [m²]
²²²R
n c
on
cen
trat
ion
[B
q/l]
meadow (n=21)
field (n=11)
forest (n=5)
0.5 1 1.5 2
(Wiegand & Feige 1999)
Vegetation
NESW
0 [m ]40 80
222Rn30
[Bq /l]
10
0
20
40
Lo e ss o n m ud -a nd sa nd sto ne s
Bo c hum e r Sc hic hte n Witte ne r Sc hic hte n
Tectonics (natural faults)
(Wiegand & Büchel 1997)
W E
0
2
4
6
810
222 R n[B q/l]
0
2
4
6
810
222 R n[B q/l]
0
2
4
6
810
222 R n[B q/l]
a lluvium
backfill
road
3.3 .1995
13.5 .1996
14.7 .1995
Tectonics (man made faults)
(Wiegand 2001)
222Rn
Rn
[Bq /l]
5
10
15
42
0 21 3 m
a lluvia l sa nd s
b a c kfill
Soil sealing
(Wiegand 2000)
0 0.40.2 0.6 0.8 1.0
0.2
0.4
0.6
1.0
2
3
4
56
2
3
4568
3.1
1.8
2.9
Soil sealing
(Wiegand 2003)
Traffic Vibrations
55
60
65
70
75
80
85
90
95
100
0 50 100 150 200 250
time [min]
²²²R
n c
on
cen
trat
ion
[B
q/l
]
(Wiegand 2003)
Traffic Vibrations
So il-g a s e xha la tio n
Traffic Vibrations (The model)
Air suc ke d into so il
No tra ffic !
Traffic Vibrations (The model)
The 10 point system
Jens Wiegand
Parameter P 1) undisturbed soil (go to 2.1) 2) layer of backfill < 3 m (go to 2.1)
2 1. Origin of soil
backfill > 3 m (go to 2.2) 0
sediment: black shale, phosphorite, bauxite magmatic rock: - silicic rocks (e.g. granite, granodiorite, syenite, monzonite,
rhyolite, dacite, pumice, pegmatite), - alkali series (e.g. phonolite, nephelinite)
metamorphic rock: orthogneiss, greisen
3
sediment: gravel, clay, pelite, carbonate rock, loess magmatic rock: intermediate rocks (e.g. diorite, andesite) metamorphic rock: clay schist, mica schist, paragneiss, granulite, marble
1
2.1 variety of rocks
sediment: sand, sandstone, conglomerate, evaporite magmatic rock: - mafic rocks (e.g. gabbro, basalt, diabase),
- ultramafic rocks (e.g. peridotite) metamorphic rock: quartzite, amphibolite, eclogite, serpentinite
0
high 226Ra conc.: slags, ashes, sewage sludge, tailings (ore mining) 3
2.
Ge
olo
gy
2.2 type of backfill low 226Ra conc.: sand, gravel, soil aggradation, rubble, tailings(coal mining) 0
upper part of hill 1
lower part of hill 0 3. Relief
plain 0
field, meadow or no vegetation 1 4. Vegetation
forest 0
tectonic elements: fault, mining subsidence 1
soil sealing > 50 % 1 5. Local parameters
strong traffic vibration (trains or trucks) < 10 m distance 1
19 May 2005
House: granite, plain, fields, railway track
Score: 7
(Wie
gand
200
1)
points low soil radon potential 0 – 3 medium soil radon potential 4 – 6 high soil radon potential 7 - 10
The 10 point system
(Wiegand in press)
Soil radon potential
0,1
1
10
100
1000
0 1 2 3 4 5 6 7 8
R2=0,94
n=3
n=10n=20
n=88
n=163n=128
n=50n=46 n=3
10 - 90%25 - 75%MeanMedian
0.5 m depth, n=511 (without tectonics, soil sealing)
²²²Rn conc. of soil-gas [Bq/l]
(Wiegand in press)
The 10 point system
Jens Wiegand
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
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
Thank you for your attention !
19 May 2005
Sebastian Feige
Helga Westerhuis
Verena Husmann
Bernd SchottSimone Tulke
Simone Schmid
Amir Yousseff
Dieter Bleile
Vegetation
P o-21 8
P o-2 16
Rn-220
+-
R n-2 22
Rn -222
Rn -22 0
Rn-22 0
P o-21 2
Po -214
Po -218
Po -21 6
B i-2 12
R n-2 22
Rn -22 2
P
P F
KF
Tr.2
Tr.1
LAK
AK
RAD7
TK
(750)
(90)(25)
(636)
(20)
(15200)
LAK: Light-Application- chamber
(n): Volume
Vegetation
(Feige & Wiegand in prep.)
Vegetation000929-1 - birch tree
0,00
500,00
1000,00
1500,00
2000,00
0,00 200,00 400,00 600,00 800,00 1000,00 1200,00 1400,00 1600,00
Duration of measurement [min]
Rad
on
[B
q/m
³]
Radon-222 [calculated]
Radon-222
Vegetation
(Feige & Wiegand in prep.)
Vegetation
0
20
40
60
80
100
120
140
160
180
200
1500
1700
1900
2100
2300
2500
2700cts/30minmm/day