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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
Study area and measurement sites
Budapest
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)
• Populated areas
Study area and measurement sites
Budapest
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)
• Grid net
– 10×10 km2
• Populated areas
Study area and measurement sites
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)
• 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”