mapping the soil gas radon concentration and soil permeability and

Mapping the soil gas radon concentration and soil permeability and their relation to pedological and

geological background

VII. Hungarian Radon Forum and Radon in Environment Satellite Workshop

2013. május 16-17., Veszprém, Hungary

Katalin Zsuzsanna Szabó1, Gyozo Jordan2, Ákos

Horváth3, László Pásztor2, Zsófia Bakacsi2, Csaba Szabó1

1Lithosphere Fluid Research Lab, Department of Petrology and Geochemistry,

Eötvös University, Budapest, Hungary ([email protected])2Institute for Soil Sciences and Agricultural Chemistry, Centre for Agricultural

Research, Hungarian Academy of Sciences 3Department of Atomic Physics, Eötvös University, Budapest, Hungary

Aims

• Take the first steps towards Hungarian geogenic radon potential mapping

• Describe the geological formations from radon, permeability and radon

potential point of view

• Understand the spatial variation of these variables

• Understand the relationship between these variables and

geological/pedological features

• Compile a geogenic radon potential map for the studied area

Selection of measurement sites

• Geological background

• Populated areas

• 10×10 km2 grid net

Middle Hungary (~5400 km2)• Geological background

– Mesozoic sedimentary rocks (limestone,dolomite)

– Tertiary volcanic rocks (andezite, dacite)

– Tertiary sedimentary rocks (marl, clay, sandstone)

– Quaternary sediments (loess,sand, fluvial sediment)

Study area and measurement sites

• Populated areas


Budapest






• Populated areas


Budapest






• Grid net

– 10×10 km2

• Populated areas







• Grid net

– 10×10 km2

• Measurement sites

– average 3 sites per cell

– altogether 192 sites

Soil gas radon concentration and soil permeability• RAD7 radon monitor (soild state semiconductor detecto, radon daughter detection)

+ soil gas probe

– GRAB protocol (30 min)

• 5 min pumping (1l/min)

• 5 min waiting for radioactive equilibrium

• 4×5 min counting (218Po)

• RADON - JOK permeameter

• Sampling depth is generally 0.8 m

Measurement methods

15 cm

RADON - JOK permeameter

RAD7 + soil gas probe

Calculation of geogenic radon potential

Geogenic radon potential (GRP)Neznal et al. (2004)

10klog

cGRP

10

GRP<10 LOW GRP

10<GRP<35 MEDIUM GRP

GRP>35 HIGH GRP

where c∞ is the equilibrium soil gas radon

concentration at a definite depth (0.8 m) (kBq m-3)

k is the soil permeability (m2)

Histogram

-2 18 38 58 78

radon

0

10

20

30

40

50

fre

qu

en

cy

Count 192Average 14.1Median 10.9Standard deviation 10.2Coeff. of variation 71.9 %MAD 5.7Minimum 1.0Maximum 47.1Range 46.2Lower quartile 6.8Upper quartile 19.2Interquartile range 12.3

Khi-squared and Kolmogorov-Smirnov tests

data follow lognormal distribution

Normal probability plot

Box-and-Whisker Plot

0 10 20 30 40 50

radon_1

Results

Soil gas radon concentration (kBq m-3)

Normal Probability Plot

0 10 20 30 40 50

radon

0.1

1

5

20

50

80

95

99

99.9

pe

rce

nta

ge

Histogram for radon

-2 18 38 58 78

radon

0

10

20

30

40

50

60

frequency

Distribution

Lognormal

Quantile Plot

0 10 20 30 40 50

radon

0

0.2

0.4

0.6

0.8

1

cu

mu

lative

pro

ba

bili

ty

Distribution

Lognormal

Results

Soil gas radon concentration

Outliers >36 kBq m-3

• Tertiary sedimentary rock: clay

• Quaternary sediments

• Proluvial-deluvial sediments

• Fluvial sediment

• Sandy loess

• Loess

(kBq m-3)

Legend

Soil gas radon concentration on different

geological formations

0

5

10

15

20

25

30

35

Tozeg

1

Bud

a÷rs

i Dolom

it For

mßci

= 1

Fut=h

omok

9

Tinny

ei F

orm

ßci=

3

Foly=

vfzi n

ledT

k (V

. ter

asz)

2

Mts

zisz

ap 2

Nag

yalf÷

ldi T

arka

agya

g For

mßci

= (b

efog

la 7

Dob

og=k

oi A

ndez

it For

mßci

= (B

÷rzs

÷ny-

Vis 2

Fodolom

it Fo

rmßci

= 1

Foly=

vfzi a

gyag

1

Fluvioe

olikus

hom

ok 2

7

Mßny

i For

mßci

= 1

Foly=

vfzi h

omok

14

V÷r

÷sag

yag

3

Foly=

vfzi-p

roluvißlis

nle

dTk

1

Mßny

i Ts T÷r

÷kbß

linti

Form

ßci= ß

tmen

ete

1

Zagyv

ai F

orm

ßci=

1

Szilß

gyi A

gyag

mßrg

a For

mßc

i= 1

Cs=

dihe

gyi D

ßcit

Tago

zat 1

Dor

ogi T

s Cso

lnok

For

mßci

= ÷ss

zevo

ntan

2

L÷sz

÷s h

omok

3

Kav

ics,

lejto

t÷rm

elTk

2

Egy

hßza

sger

gei T

s G

arßb

i For

mßc

i= ÷

ssze

v 1

Hom

okos

l÷sz

7

Hom

okos

l÷sz

, l÷s

z÷s

hom

ok 2

L÷sz

30

Nag

yalf÷

ldi T

arka

agya

g For

mßci

= 3

SzT

pv÷l

gyi M

Tszko

F. 3

Folyo

vizi a

leur

it 6

Foly=

vfzi a

leur

itos

hom

ok 2

Hßr

sheg

yi H

omok

ko F

orm

ßci=

2

T÷r÷k

bßlin

ti Hom

okko

For

mßci

= 3

Hidro

eolik

us a

gyag

os l÷

sz 3

Deluv

ißlis

aleur

it 2

Foly=

vfzi n

ledT

k 27

Egy

hßza

sger

gei F

orm

ßci= 1

Dac

hste

ini m

Tszko

F. 1

Kisce

lli A

gyag

For

mßci

= 2

Nag

yv÷l

gyi D

ßcittu

fa F

orm

ßci= (B

÷rzs

÷ny-

4

Deluv

ißlis

agy

ag, h

omok

1

Pro

luvißlis

-deluv

ißlis

nledT

k 3

GEO_név

me

dia

n

MedianGr1

Gr2

Gr3

0

5

10

15

20

25

Drift sand 9

Fluvioeolic sand 27

Fluvial sand 14Loess 30

Fluvial sediment 27

geological formation

me

dia

n

Median

• 41 geological formations

• median of the measured soil gas radon concentrations of the geological formations

• 3 groups

• 5 geological formations have >8 data

1

2

3

Legend

Gr1 (>28 Bq m-3)

• Quaternary proluvial, deluvial sediments (3)

Soil gas radon concentration on different geological formations

Pilisszentlászló

1

2

3Püspökhatvan

Galgagyörk

Galgamácsa

1

2

3

Gr1 (medsoilRn>28 Bq m-3)

• Quaternary proluvial, deluvial sediments (4)

Gr2 (medsoilRn: 20-28 Bq m-3)

• Tertiary (Miocene) dacite (1)

• Tertiary sedimentary clay (4)

• Mesozoic limestone (2)

• Tertiary sandstone (1)

• Quaternary fluvial sediment (27)

Gr3(medsoilRn < 20 Bq m-3)

• Quaternary loess (30)

• Quaternary fluvial sand (14)

• Quaternary fluvioeolic sand (27)

• Quaternary drift sand (9)

• etc.

n>8

Soil gas radon concentration on different geological formations

Soil gas radon concentration in case

of different soil texture

Median

6

8

10

12

14

16

18

20

Sand 68 Rocky 5 Light loam 44 Loam 63 Heavy loam clay 4

soil texture

Soil

gas

rad

on

co

nce

ntr

atio

n (

kBq

m-3

)

Soil gas radon concentration in case of different

chemical behaviour

median

0

5

10

15

20

25

Rocky, gravelly 3 mainly acid, upper soil

is unsaturated with

chalk, lower soil

contains carbonated

chalk 29

mainly neutral or

alkalescent,

unsaturated with chalk

143

mostly acid, upper soil

is unsaturated with

chalk, lower soil do not

contains carbonated

chalk 9

Soil

gas

rad

on

co

nce

ntr

atio

n (

kbq

m-3

)

Eredmények

Soil permeability

Count 192

Average -26.2

Median -26.2

Standard deviation 1.8

Coeff. of variation -6.9%

MAD 1.4

Minimum -29.9

Maximum -20.8

Range 9.2

Lower quartile -27.7

Upper quartile -24.9

Interquartile range 2.8

Histogram

-31 -29 -27 -25 -23 -21 -19

log(permea)

0

10

20

30

40

fre

qu

en

cy

Box-and-Whisker Plot

-30 -28 -26 -24 -22 -20

log(permea)

ln(permea)= -26.7 (=2.5E-12 m2)

Eredmények

Soil permeability

Eredmények

Soil permeability

Categorization (Neznal et al., 2004)

high k >4E-12

medium k 4E-12>k>4E-13

low k <4E-13

Soil permeability on different geological formations

-30

-29

-28

-27

-26

-25

-24

-23

-22

-21

-20

med

(lo

g((

perm

ea))

geonev

-27

-26.5

-26

-25.5

-25

-24.5

-24

Loess 30

Fluvial sand 14

Fluvial sediment 29

Fluvioeolic sand 31

Drift sand 9

geological formation

me

d(lo

g((

pe

rme

a))

med(permea)

Soil gas radon concentration and soil permeability on different

geological formations

R2 = -0.42

R2 = -0.92

0

5

10

15

20

25

Drift sand 9

Fluvioeolic sand 31

Fluvial sand 14Loess 30

Fluvial sediment 29

Geo_nev

-27

-26.5

-26

-25.5

-25

-24.5

-24

soil radon

permea

Eredmények

Count 192

Average 11.9

Median 8.7

Standard deviation 14.6

Coeff. of variation 121.9%

MAD 4.7

Minimum -50.1

Maximum 73.9

Range 124.1

Lower quartile 4.7

Upper quartile 15.5

Interquartile range 10.7

GRP<10 low

10<GRP>35 medium

GRP>35 high

GRP (geogenic radon potential)

Results

Geogenic radon potential (GRP)Neznal et al. (2004)

10klog

cGRP

10

Based on Czech data (Barnet and

Pacherova, 2010)

GRPIndoor radon

concentration

Low

(<10)<200 Bq m-3

Medium

(10-35)200-400 Bq m-3

High

(>35)>400 Bq m-3

where c∞ is the equilibrium soil gas radon

concentration at a definite depth (0.8 m) (kBq m-3)

k is the soil permeability (m2)

-20

-10

0

10

20

30

40

50

60

70

80Fo

lyóv

ízi-

prol

uviá

lis ü

ledé

k 1

Més

zisz

ap 2

Toze

g 1

Dob

ogók

oi A

ndez

it F

orm

áció

2

Vör

ösag

yag

3M

ányi

és

Törö

kbál

inti

For

mác

ió á

tmen

ete

1

Nag

yalf

öldi

Tar

kaag

yag

Form

áció

7

Csó

dihe

gyi D

ácit

Tag

ozat

1Fo

lyóv

ízi h

omok

14

Futó

hom

ok 9

Bud

aörs

i Dol

omit

For

mác

ió 1

Foly

óvíz

i ale

urit

7

Hom

okos

lösz

, lös

zös

hom

ok 2

Lösz

ös h

omok

3

Fodo

lom

it F

orm

áció

1Eg

yház

asge

rgei

és

Gar

ábi F

orm

áció

öss

zev

1

Törö

kbál

inti

Hom

okko

For

mác

ió 3

Hid

roeo

likus

agy

agos

lösz

3N

agya

lföl

di T

arka

agya

g Fo

rmác

ió 3

Mán

yi F

orm

áció

1Fl

uvio

eolik

us h

omok

28

Foly

óvíz

i üle

dék

(V. t

eras

z) 2

Hom

okos

lösz

7Lö

sz 3

0

Foly

óvíz

i ale

urit

os h

omok

3D

eluv

iális

ale

urit

2

Zagy

vai F

orm

áció

1

Foly

óvíz

i üle

dék

27D

achs

tein

i més

zko

F. 1

Kavi

cs, l

ejto

törm

elék

2Ti

nnye

i For

mác

ió 3

Kisc

elli

Agy

ag F

orm

áció

2

Dor

ogi é

s C

soln

ok F

orm

áció

öss

zevo

ntan

2H

ársh

egyi

Hom

okko

For

mác

ió 2

Nag

yvöl

gyi D

ácit

tufa

For

mác

ió (

Bör

zsön

y- 4

Prol

uviá

lis-d

eluv

iális

üle

dék

3

Szilá

gyi A

gyag

már

ga F

orm

áció

2

Egyh

ázas

gerg

ei F

orm

áció

1Sz

épvö

lgyi

Més

zko

F. 2

Del

uviá

lis a

gyag

, hom

ok 1

ResultsGRP in case of different geological formations

median of GRP values

n>8

border of low-medium GRP

border of medium-high GRP

Geogenic radon

potential map of the

study area

lowmediumhigh

GRP

no data

Based on our 192 data

GRP of

the areaGRP of sites

Low

(<10)

69% low

28% medium

3% high

Medium

(10-35)

29% low

58% medium

13% high

High

(>35)

0% low

0% medium

100% high

Legend

0.69

0.29

0.0

0.28

0.58

0.0

0.030.13

1.0

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

LOW MEDIUM HIGH

Percentage of low, medium and high GRP sites on the different GRP areas

HIGH

MEDIUM

LOW

Summary

Soil gas radon concentration data

• soil gas radon concentration data follow lognormal distribution

• it has spatial pattern and relationship to geological background, soil texture and soil chemical behaviour

Soil permeability data

• there is no pattern in the soil permeability spatial distribution

• it has relationship to geological background

• there is negative linear correlation between soil gas radon concentration and soil permeability

Geogenic radon potential

• it has relationship to geological background

• most of the study area has low and medium GRP

• medium GRP: Quaternary fluvial sediment

• high GRP in case of proluvial-deluvial sediments

Thank you very much for

your attention!

Anna Dömök

Tamás Gábner

Zsuzsanna Szabó

Roland Helf

Hédi Nagy (ELTE TTK)

Péter Völgyesi (ELTE TTK)

Doctoral School for Environmental Sciences, Eötvös University

Acknowledgement

The research was founded by the European Union and Hungary in the framework of the

TÁMOP 4.2.4.A/1-11-1-2012-0001 “National Excellence Program - National Program for

elaboration and run a system for personal support for Hungarian students and researchers”

mapping the soil gas radon concentration and soil permeability and

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