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