ORIGINAL PAPER

Radioactive element contents of some granites used as buildingmaterials: insights into the radiological hazards

Nurdan Sayın

Received: 30 May 2013 / Accepted: 12 September 2013 / Published online: 16 November 2013

� Springer-Verlag Berlin Heidelberg 2013

Abstract This study was conducted to investigate the

radioactive potential hazard of granite, which is widely used

as building material in Turkey. Natural radiation levels of 18

various, globally-distributed industrial granite samples

imported by Turkey, were analyzed using gamma-ray

spectrometer. The results are compared with the formerly

published findings of granite samples from Turkey. Radio-

activity levels of 238U, 232Th, and 40K natural radioactive

series elements of the selected 18 specimens were measured,

which were from 2.4 ± 0.5 to 88.8 ± 3.6 Bq kg-1 for 238U,

from 2.4 ± 0.7 to 273 ± 0.9 Bq kg-1 for 232Th, and from

169 ± 24 to 1,479 ± 94 Bq kg-1 for 40K. Radium equiva-

lent activities (Raeq) were calculated for the granite samples

to assess their radiation hazards in the construction of

dwellings. The Raeq values of granite samples varied in the

range of 39.05–570 Bq kg-1, only one sample exceeded the

safe limit value of 370 Bq kg-1 set by the OECD-NEA

(Nuclear Energy Agency. Exposure to radiation from natural

radioactivity in building materials. Report by NEA Group of

Experts 1979). Absorbed dose rates in air were found

between 18.74 and 261 nGy h-1 and radiogenic heat pro-

duction values were calculated in the range of

0.45–6.53 lW m-3. All rock samples used in this study were

also analysed mineralogically and defined their

compositions.

Keywords Granite � Radioactive elements �Building industry � Radiological hazard �Radiogenic heat

Introduction

All living beings on earth are exposed to cosmic radiation

emitted from the universe and terrestrial radiation from

natural radioactive elements and compounds during their

lifetime. Terrestrial natural radiation is produced from

primordial radionuclides located in the crust of the earth

since it was formed (4.5 9 109 year). The most important

radionuclides in terms of radiological risk are uranium

(238U), thorium (232Th), and potassium (40K) and the nat-

ural radioactive decay products of these series. Rubidium87Rb and 235U are in the second order of primordial ra-

dionuclides importance and their contributions to radiation

doses received by people from these radionuclides are at a

negligible level.

The concentrations of 238U, 232Th, and 40K in the

building materials significantly contribute to the environ-

mental radioactivity that vary from region to region,

depending on the geological and geochemical characteris-

tics of the region (Whitfield et al. 1959; Rogers and Ra-

gland 1961; Doventon and Prensky 1992). The worldwide

average concentrations of these radionuclides were repor-

ted by United Nations Scientific Committee on the Effects

of Atomic Radiation (UNSCEAR 2000) as 30, 35, and

400 Bq kg-1 for 238U, 232Th, and 40K, respectively.

Because of an increase in environmental awareness,

radiologic effects of natural rocks used as building mate-

rials are the subject of several studies, which investigate

the impacts of the radioactivity of building materials to

human health and the environment, in not only Turkey, but

also in other countries and regions (Othman and Mahrouka

1994; Carrera et al. 1997; Rizzoa et al. 2001; Amrania and

Tahtat 2001; El-Shershaby 2002; Tzortzis et al. 2003;

Turkmen et al. 2003; Ustaomer et al. 2005; Ahmed 2005;

Orgun et al. 2005, 2007; Anjos et al. 2005; Pavlidou et al.

N. Sayın (&)

Department of Geophysical Engineering,

Faculty of Engineering, Istanbul University,

34320 Avcılar, Istanbul, Turkey

e-mail: nursayin@istanbul.edu.tr

123

Bull Eng Geol Environ (2013) 72:579–587

DOI 10.1007/s10064-013-0525-0

2006; Cetin et al. 2012; Kovler 2012). These studies and

observations present valuable information regarding the

local radionuclide characteristics of building materials.

They also provide useful general information and meth-

odologies about health and environmental hazards of

radioactive substances in the building materials.

Turkey has an exponentially growing building and

building material industry. As a result, the increasing need

for building stones is supplied by increasing domestic

production as well as extensive import trade of building

stones such as granites. For this reason, several building

stone specimens are collected in the Turkish market. The

main purpose of this study is to determine radioactivity

level of the granites used in the building industry. People

mostly spend their time inside the buildings, and granites

are widely used in interior spaces as well as exterior

coatings; this expanded use of granites makes it important

to know the radioactivity levels in order to prevent possible

hazards.

Therefore, the current levels of 238U, 232Th, and 40K

radiation were assessed in some granitic rocks that are

widely used in Turkey and the related health risks were

estimated. In addition, the amounts of heat converted from

the radioactivity of materials were used to estimate the

values of radiogenic heat production formed by these ra-

dionuclides. The analyses were carried out using a high-

resolution gamma-ray spectrometry technique. The radio-

activity levels obtained from the granite samples imported

from various countries were also compared with the granite

samples produced domestically. Furthermore, mineralogi-

cal compositions of all samples were defined under a

polarized microscope.

Materials and methods

Materials

Eighteen industrial granite samples imported from abroad

and widely used in Turkey were selected for this study. The

original region and country of these samples are presented

in the first column of Table 1 and the photos of some

samples are given in Fig. 1. Mineralogical compositions

and textures of these samples were studied using an optical

microscope. The experiments were performed to determine

radioactive elements concentrations.

The granite samples, each weighing ca. 1,600–1,700 g,

were pulverized, sieved through 0.2 mm mesh, sealed in

standard 1,000 ml Marinelli beakers, dry-weighed and

stored for 4 weeks before further experiments to allow

reaching the equilibrium between 226Ra and 222Rn and their

decay products. Radioactivity measurements were then

performed using gamma spectrometry system in the labo-

ratory of the Istanbul Cekmece Nuclear Research and

Training Center, Turkey. Radioactivity values of 238U,232Th, and 40K were used to calculate the radium equiva-

lent activities, gamma-ray dose, and indoor and outdoor

gamma radiation rates. The analytical technique and

Table 1 Samples names, radioactivity concentrations Raeq activities (in Bq kg-1), gamma radiation doses (in nGyh-1), indoor, outdoor (nSv)

and radiogenic heat production values (in lWm-3)

Sample name 238U 232Th 40K Raeq Gamma radiation

dose

Indoor Outdoor Radiogenic

heat

1 Canada Blue Eyes 9.78 ± 0.6 17.3 ± 0.6 674 ± 31 86.42 44.61 0.21 0.05 0.70

2 Ukranian Santiago Red 50.1 ± 2.1 91.2 ± 2.7 1,120 ± 71 266.76 129.93 0.62 0.15 2.93

3 Hint New Imperial 12.4 ± 0.8 20.1 ± 1 884 ± 50 109.21 56.61 0.27 0.07 0.87

4 Hint Star Galaxy 10.8 ± 1 10.8 ± 0.8 169 ± 24 39.26 19.03 0.09 0.02 0.46

5 Hint Paradiso 2.4 ± 0.5 2.4 ± 0.7 571 ± 48 49.80 27.17 0.13 0.03 0.26

6 China Xili Red 64.8 ± 2.9 88 ± 3.7 1,324 ± 88 292.59 142.86 0.69 0.17 3.24

7 Brazil Verde Marinage 26 ± 1.8 39 ± 2 1,427 ± 94 191.65 98.28 0.47 0.12 1.63

8 Italy Rosa Beta 31.2 ± 1.9 44.2 ± 2.1 1,032 ± 74 173.87 6.96 0.42 0.10 1.71

9 China Super Violet 66.2 ± 3.1 69.6 ± 3.1 1,098 ± 78 250.27 119.59 0.59 0.15 2.89

10 Espanol Rosewel 88.8 ± 3.6 55.9 ± 2.7 1,479 ± 94 282.62 138.52 0.67 0.17 3.25

11 Espanol Crema Perla 47.5 ± 2.4 97.8 ± 4.0 1,235 ± 86 282.45 138.13 0.66 0.16 3.02

12 China Bianco Sardo 84.6 ± 2.8 136 ± 4 1,130 ± 61 366.09 174.75 0.84 0.21 4.41

13 Hint Imperial Red 70.8 ± 3.3 273 ± 9 1,424 ± 93 570.84 272.19 1.28 0.32 6.54

14 Brazil Cafe Imperial 13.81 ± 1.7 21.77 ± 2.3 554 ± 33 87.60 44.13 0.21 0.05 0.82

15 Espanol Rosa Minho 26.38 ± 3.1 40.68 ± 3.7 675 ± 18 136.53 67.22 0.32 0.08 1.44

16 Hint Himalayan Blue 9.89 ± 1.2 13.81 ± 2.6 481 ± 39 66.71 34.07 0.16 0.04 0.59

17 Espanol Rosa Porino 85 ± 2.2 111 ± 7 1,212 ± 17 337.01 158.74 0.78 0.19 4.02

18 African Granite 72 ± 4.6 101 ± 6.1 1,310 ± 18 317.02 150.61 0.73 0.18 3.64

580 N. Sayın

123

calculation methods are described below. The results are

presented in Table 1.

Radioactivity measurement

The gamma-ray spectrometer system used to determine the

radioactivity of the samples consists of 184 cc HPGe

coaxial detector with relative efficiency of 25 %,

1.33 MeV gamma ray of 60Co full width at half maximum

(FWHM): 1.83 keV and pick: Compton ratio of 57:1, Ortec

Model-671 spectroscopic amplifier and based 8192 channel

Canberra in a PC computer pulls height analyzer and

related electronic accessories. The detector was internally

shielded in a 10 cm thick lead.

A multi-gamma-ray reference standard sample type

MGS-5 (Canbera Industries, Inc., USA) was used for cal-

ibration of detector efficiency with the same geometry as

the measured for a period of 50,000 s. The gamma ray

transitions of energies 186.3 (226Ra), 351.9 (214Pb), and

609.3 keV (214Bi) were used to determine the concentra-

tion of 238U series. The gamma-ray lines at 911.0 (228Ac)

and 583.3 keV (208Tl) were used to determine the con-

centration of the 232Th series. The activity of 40K was

estimated using the 1,461 keV peak.

The x axis of the spectra represents the energy values in

keV corresponding to different gamma peaks of interest

radionuclides. The net sample count rate under the most

prominent photo peaks of U and Th daughter peaks were

calculated through subtracting the relevant count rate from

the background spectrum resulted from the same counting

time. Then, the activity of the radionuclide was calculated

from the background subtracted area prominent gamma ray

energies. The concentrations of radionuclides were calcu-

lated using Eq. (1):

A ¼ Na

ePtwðBq kg�1Þ ð1Þ

where Na is the net count for the gamma-rays, e is the

counting efficiency of the detector, P is the absolute tran-

sition probability for gamma decay per transformation, t is

the counting time in seconds and w is the weight of the

dried sample in kilograms.

Fig. 1 Photos of some samples

examined. a Espanol Rosawel,

b China Super Violet, c Hint

Paradiso, d China Bianco Sardo,

e China Xili Red, f Espanol

Crema Perla, g Italy Rosa Beta,

h Hint Imperial Red, i Brazil

Verde Marinage

Granites used as building materials 581

123

Radium equivalent activity

To represent the activity levels of 238U, 232Th, and 40K,

which take into account the radiological hazards associated

with them, a common radiological index has been intro-

duced. This index is called radium equivalent activity

(Raeq) and is mathematically defined by Eq. (2) (Beretka

and Mathew 1985; UNSCEAR 2000):

Raeq Bq kg�1� �

¼ AU þ 1; 43 ATh þ 0:077 AK ð2Þ

where AU, ATh and AK are the specific activities of 238U,232Th, and 40K, respectively. This equation is based on the

estimation that 10 Bq kg-1 of 238U equal 7 Bq kg-1 of232Th and 130 Bq kg-1 of 40K produced equal gamma

dose. The maximum value of Raeq must be less than

370 Bq kg-1 (UNSCEAR 2000).

Absorbed dose rate in air

Absorbed dose rate is defined as the ratio of an incremental

dose (dD) in a time interval (dt), shown in Eq. (3):

AD ¼ dD=dt ð3Þ

Gamma dose rate in air, one meter above the ground, is

used for the description of terrestrial radiation, usually

expressed in nGy h-1 or pGy h-1. The absorbed dose rate

due to gamma radiation of naturally occurring

radionuclides (238U, 232Th, and 40K) were calculated

based on the guidelines provided by Eq. (4) (UNSCEAR

2000):

AD nG h�1� �

¼ 0:462 AU þ 0:621 ATh þ 0:0417 AK ð4Þ

where 0.462, 0.621, and 0.0417 are the conversion factors

for 238U, 232Th, and 40K, respectively, assuming that the

contribution of the naturally occurring radionuclide can be

neglected as they only contribute slightly to the total dose

resulting in from the environmental background.

Annual effective doses

To estimate the annual effective doses, two factors must be

considered: (a) the conversion coefficient from absorbed

dose in air to the effective dose, and (b) the indoor occu-

pancy factor. The average numerical values of those

parameters vary with the age of the population and the

climate at the considered location. In the UNSCEAR

(1993) Report, the Committee used 0.7 Sv Gy year-1 for

the conversion coefficient from absorbed dose in air to the

effective dose received by adults and 0.8 for the indoor

occupancy factor the fraction of time spent indoors and

outdoors were considered as 0.8 and 0.2, respectively.

These values were retained in the present analysis. The

annual effective doses are determined using Eqs. (5) and

(6) (UNSCEAR 1993):

Indoor nSvð Þ ¼ absorbed dose in nGy h�1 � 8760 h

� 0:8� 0:7 Sv Gy year�1 ð5Þ

Outdoor nSvð Þ ¼ absorbed dose in nGy h�1 � 8760 h

� 0:2� 0:7 Sv Gy year�1: ð6Þ

The resulting worldwide average of the annual effective

dose is 0.48 mSv, with the results for individual countries

being generally within the range of 0.3–0.6 mSv. The

values of effective dose are almost 10 and 30 % larger for

children and infants, respectively, which are in direct

proportion to an increase in the value of the conversion

coefficient from absorbed dose in air to effective dose.

Radiogenic heat production

The variations in the radiogenic heat production are

attributed to characterize the different type rocks. In order

to calculate radiogenic heat production the radionuclides

concentration in Bq kg-1 is converted to parts per million

(ppm) using the appropriate conversion factors. The spe-

cific parent activity of a sample containing 1 ppm of 232Th

and 1 ppm of natural 238U are 4.08 and 13.0 Bq kg-1,

respectively. For natural potassium, a concentration of

1 wt% of sample corresponds to a 40K-specific activity of

317 Bq kg-1.

On the basis of well-known isotropic decay schemes, the

half-lives, and mass, the quantity of heat generated per

second and kilogram by 40K, 238U, and 232Th are: natural

uranium 9.52, thorium 2.56 and natural potassium 3.48,

and q is density of granite samples in kg m-3. The heat

(Qr) produced by radioactivity in a rock with concentra-

tions of CU, CTh and CK (in ppm) were computed using Eq.

(7) (Rybach 1988):

Qr ¼ q 9:52 CU þ 2:56 CTh þ 3:48 CKð Þ� 10�5 lW m�3

� �ð7Þ

This property is expressed as the radiogenic heat produc-

tion rate per kilogram.

Results

Mineralogical analyses

Thin sections of rock samples were studied under a

polarized microscope in order to determine their mineral-

ogical compositions and investigate their textures. Miner-

alogical and textural properties of all samples were given in

Table 2. While most of the samples are granites, two

582 N. Sayın

123

samples were defined as anorthosite and meta-arkosic

(granite-derived) conglomerate. While the term ‘granite’ is

used to describe all igneous rock types used as building

materials in stone market, mineralogical composition of

Canada Blue Eyes and Brazil Verde Marinage show that

these samples are not granite (Table 2).

Most of the samples display granular and holocrystalline

granular textures (Fig. 2). A few samples show cataclastic

textures indicating post-crystallisation brittle deformations.

The defined rock forming minerals of granitic rocks are

quartz, alkali feldspar (orthoclase and microcline), pla-

gioclase, biotite, muscovite, accessory minerals (zircon,

apatite and allanite) and opaque minerals (Fig. 2a, b). The

accessory minerals occur either as individual grains

(Fig. 2c) or as inclusions in orthoclase, hornblende and

biotite. Radioactive pleochroic haloes are common around

zircon inclusions in biotites (Fig. 2d). Some granitic sam-

ples show variable alterations such as kaolenization, seri-

citation and chloritization.

Radioactivity measurements

We measured radioactivity values of 18 imported industrial

granite samples and calculated the radium equivalent

activities (Raeq) to estimate the related health risks by

comparing world average values reported by the OECD-

NEA (1979) of 370 Bq kg-1.

The measurements in this study showed that, the mean

activity concentration of 238U was found to be in the range

from 2.4 ± 0.5 to 88.8 ± 3.6 Bq kg-1 while for 232Th, it

Table 2 Mineralogical definitions of the studied samples

Sample name Color Texture Rock type Minerology Alterations

1 Canada Blue Eyes Gray–yellow Granular Mafic-magmatic Ort, Pl, Cpx, Bi, Ap –

2 Ukranian

Santiago Red

Red–black Granular Quartz-monzonite Pl, Ort, Amp, Bi, Hb, Zr –

3 Hint New

Imperial

Red Cataclastic Meta-granite Ort, Qz, Pl, Bi, Chl, Zr, Op Pertitization

4 Hint Star Galaxy Black Granular Granite Qz, Ort, Per, Pl, Bi, Chl Pertitization

5 Hint Paradiso Brown Cataclastic Meta-granite Qz, Ort, Pl, Bi, Mu, Ap, Zr, Op –

6 China Xili Red Pink white Holocrystalline

granular

Granite Qz, Ort, Pl, Bi, Chl, Tit, Zr, Ap,

Op

Chloritization

7 Brazil Verde

Marinage

Green Granular Meta-conglomerate Qz, Pl, Op, Zr –

8 Italy Rosa Beta Dark gray pink Holocrystalline

granular

Siyenite Ort, Pl, Qz, Bi, Chl, Mu, Ep,

Ser, Zr, Op

Chloritization

9 China Super

Violet

Gray pink white Granular Granite Qz, Ort, Pl, Bi, Clr, Zr, Tit, Op Pertitization

10 Espanol Rozewel Light pink white Granular Granite Ort, Qz, Pl, Bi, Zr, Op, Chl Kaolinization

sericitization

11 Espanol Crema

Perla

Light yellow Granular Granite Ort, Mic, Pl, Qz Per, Bi, All, Zr,

Ap

–

12 China Bianco

Sardo

White light gray Holocrystalline Granite Qz, Pl, Ort, Zr, Op Chloritization

sericitization

13 Hint Imperial Red Red Cataclastic Meta-granite Ort, Mic, Per, Qz, Pl, Bi, Chl,

Zr, Op

Chloritization

14 Brazil Cafe

Imperial

Brown Granular Granite Qz, Pl, Bi, Amp, Zr, Ap, Op Kaolinization

15 Espanol Rosa

Minho

Gray light pink

black

Granular Monzo-granite Ort, Qz, Pl, Bi, Hb, Chl, Op –

16 Hint Himalayan

Blue

Gray Granular Granite Ol, Pl, Qu, Ap, Chl –

17 Espanol Rosa

Porino

Pinkish Granular Granite Qu, Ort, Pl, Bi, Chl, Zi, All, Op –

18 Arfican Granite Dark red Holocrystalline Granite Qz, Ort, Pl, Chl, Bi, Zr, Ap Chlaritization

The classification of rock type was done according to Streckeisen (1976)

Qz quartz, Pl plagioclase, Ort orthoclase, Bi biotite, Hb hornblend, Amp amphibole, Cpx clinopyroxene, Per pertite, Mu muscovite, Ol olivine, Zr

zircon, Tit titanite, Mic microcline, Chl chlorite, Ep epidote, Ap apatite, All allanite, Op opaque minerals

Granites used as building materials 583

123

was in the range of 2.4 ± 0.7 and 273 ± 0.9 Bq kg-1

(Table 1). On the other hand, the activity of the 40K was

found in the range of 169 ± 24 and 1,479 ± 94 Bq kg-1.

Raeq values were calculated for the samples to assess the

radiation hazards arising from the use of these materials in

the construction of dwellings. The Raeq values of the

Fig. 2 General view of the some granite samples under the optical microscope. a Hint Imperial Red, b Canadian Blue Eyes, c Espanol Rosa

Porino, d Hint Star Galaxy. Abbreviations are given in Table 2

Fig. 3 Comparison of activity concentrations of 238U, 232Th, 40K and Raeq values (in Bq kg-1) of the imported granite samples examined in this

study

584 N. Sayın

123

granite samples varied between 39.05 and 570 Bq kg-1,

only one sample exceeded the limit value set by the report

of the OECD-NEA (1979) with the value of 370 Bq kg-1.

The results of activity concentrations are given in Table 1

and Fig. 3.

Absorbed dose rates in air were calculated between

18.74 and 261 nGy h-1. The corresponding indoor and

outdoor annual effective doses were in the range of

0.09–0.84 mSv. The results are shown in Table 1 with the

sample (number 13, Hint Imperial Red) exceeding the safe

limit. Besides, three of the India originated specimens (3, 4,

5 in Table 1) showed the lowest radioactivity level, with

the accompany of Brazil and Canada originated two other

samples (1 and 14 in Table 1), among the all other samples.

In this study because radiogenic heat production values

of the samples are an indication of high level of radioactive

elements, thus these calculations are made and found 0.45

and 6.53 lW m-3 (in Table 1 last column).

Discussion

The accessory minerals in the samples are responsible from

radioactivity content. While Hint Imperial Red and Espa-

nol Rosa Porino show the high activity concentration of

values (Fig. 2a, c respectively) Canadian Blue Eyes and

Hint Star Galaxy have lower radioactivity values (Fig. 2b,

d). According to mineralogical content of the samples,

accessory minerals such as allanite, monazite, zircon and

apatite can be shown in the rocks which have high U and

Th values (for example Hint Imperial Red and China Bi-

anco Sardo). High K content is related to alkali feldspars,

plagioclases and micas (example Chine Xili Red and Es-

panol Rosawel). The high activity concentrations related to

mineralogical composition of the granite samples has been

reported in detail in Orgun et al. (2005, 2007), Pavlidou

et al. (2006), Cetin et al. (2012).

The worldwide average concentrations of radionuclides

were reported by the United Nations Scientific Committee

on the Effects of Atomic Radiation (UNSCEAR) as 30, 35,

and 400 Bq kg-1 for 238U, 232Th, and 40K, respectively.

An important feature of the radionuclides in the rocks is

their emission of heat to the environment. The amount of

heat released is proportional to the amount of radioactive

elements in the rock. Even if you are not familiar with the

radioactivity of the rocks, temperature values can give an

idea about the radioactivity. Therefore, in this study,

radiogenic heat production values for the samples analyzed

were calculated and found between 0.45 and 6.53 lW m-3

(Table 1).

According to the findings of earlier studies conducted in

Turkey, granites emit larger values of radioactivity than

other stones. It was reported that concentrations of U, Th,

and K are 3–6 times larger in Kestanbol granites (Orgun

et al. 2007; Merdanoglu and Altınsoy 2006). It was also

reported that the mean absorbed dose rate in outdoor air in

the Kaymaz and Sivrihisar plutons are respectively almost

six and three times larger than those of the worldwide

Table 3 Summary of activity concentration (Bq kg-1) of naturally occurring 238U, 232Th and 40K radioisotopes in granite samples from work

conducted in regions around the Turkey

Region 238U 232Th 40K References

Cyprus 1–588 1–906 50–1,606 Tzortzis et al. (2003)

Italy 38 60 1,103 Carrera et al. (1997)

Gable Gattar, Egypt 165 ± 75 to

27,851 ± 836

71 ± 2 to

274 ± 8

1,048 ± 31 to

1,230 ± 37

El-Shershaby (2002)

Qena, Egypt 187 ± 90 118 ± 14 852 ± 297 Ahmed (2005)

Ankara Turkey 67.5 ± 47.6 77.4 ± 53.0 915.3 ± 361.2 Turhan et al. (2008)

Ikizdere-Uzungol Turkey 15.85 33.76 359 Osmanlıoglu (2006)

Eskisehir (Kaymaz), Turkey 306.5 248 1,265.6 Orgun et al. (2005)

Eskisehir (Sivrihisar), Turkey 67 152.8 1,057.7 Orgun et al. (2005)

Kestanbol (Ezine-Canakkale) 174.78 204.66 1,171.95 Orgun et al. (2007)

Kestanbol, Turkey 192 115 1,207 Merdanoglu and Altınsoy (2006)

Kestanbol, Turkey 94–637 (226Ra) 120–601 1,074–1,527 Canbaz et al. (2010)

Aksaray Yaylak granite

Turkey

82 ± 3 62 ± 2 1,082 ± 13 Turkmen et al. (2003)

Kozak granite Turkey 97 ± 6 73 ± 3 972 ± 13 Turkmen et al. (2003)

Kozak granite Turkey 29–111 35–87 698–1,100 Karadeniz et al. (2011)

Granite (Turkey) 98 83 860 Ustaomer et al. (2005)

Worldwide average 30 35 400 UNSCEAR (2000)

Granites used as building materials 585

123

average values (Orgun et al. 2005). As seen from Table 3

and Fig. 4 the calculated Raeq activities of the Kaymaz

pluton (with as average of 758.59 Bq kg-1) were found to

be larger than the recommended maximum value of

370 Bq kg-1. The Raeq values for Kestanbol granites were

calculated within 368–1,614 Bq kg-1 range while the

values of the hazard index (Hex) based on the criterion

formula are larger than unit (Orgun et al. 2007; Canbaz

et al. 2010). It was reported that Raeq values for Aksaray

Yaylak and Kozak granites are in the normal limits of

253 ± 12 and 275 ± 20 Bg kg-1, respectively (Turkmen

et al. 2003).

Table 3 represents a summary of recent results on nat-

ural gamma radioactivity levels derived from similar

investigations conducted in close regions for comparison.

Tzortzis et al. (2003) studied on 28 different granite sam-

ples imported to Cyprus, El-Shershaby (2002) gave the

measurements about radioactivity of 50 granites from

Gable Gattar. Carrera et al. (1997) and Ahmed (2005)

studied on building materials included granite samples. As

seen from Table 3 activity concentrations some region

samples are extensively high such as 238U are for Cyprus

samples range 1–588 and for Gable Gattar the value is

27,851 Bq kg-1. The corresponding activity concentra-

tions of the 232Th, 238U, and 40K radioisotopes obtained

from this study fall within the smallest range of most

reported values from other neighboring areas except one

sample. When the results of this study are compared with

the results of the previous studies (Pavlidou et al. 2006;

Cetin et al. 2012), it is clear that obtained values from this

study are lower and there are moderate radioactivity levels

for the common investigated granite samples.

The radium-equivalent activities obtained for the

building materials in this study were found to be below the

criterion limit of 370 Bq kg-1, except one sample. There-

fore, the use of these materials in construction of dwellings

can be considered safe for inhabitants according to the

values provided in the report by the OECD-NEA (1979).

The data obtained and collected in this study may con-

tribute to expand a the data base of physical properties of

granites and, the information it seems now as secondary

findings, will gain importance in future. So parameters

such as absorbed dose rates in air and radiogenic heat

production values are included in this study for the future

needs and comprehension.

Conclusion

The variations in the activity concentrations of radionuc-

lides for 18 imported industrial granite samples were ana-

lyzed. The gamma-ray spectrometry measurement system

was used to determine the radioactivity levels of 238U,232Th, and 40K samples. The mean value activity concen-

tration of 238U in samples was found as 2.4 ± 0.5 and

88.8 ± 3.6 Bq kg-1 while for 232Th it was found in the

range of 2.4 ± 0.7 and 273 ± 0.9 Bq kg-1. The activity of

the 40K was found in the range of 169 ± 24 and

1,479 ± 94 Bq kg-1. These results can be considered as

the base values for the average content of granites used as

building material in Turkey. The values of Raeq for the

granite samples varied between 39.05 and 570 Bq kg-1,

only one sample exceeded the limit value set by the OECD-

NEA (1979) report. Absorbed dose rates in air were

observed between 18.74 and 261 nGy h-1. Radiogenic

heat production values were calculated between 0.45 and

6.53 lWm-3. The observations in this study lead to the

final conclusion that the examined building materials, with

one exception, emit radiations below the hazard limit and,

therefore, are safe to be used in the buildings. Radioactivity

contents of the samples are consistent with the mineral-

ogical composition of the granite samples. The source of

high radioactivity of the samples (i.e., Hint New Imperial)

is mainly presence in large amount of orthoclase and

radiogenic accessory minerals.

Comparison of the results from imported and domesti-

cally produced granite specimens showed that two pro-

duced around Turkey and one imported from abroad are

not within safe limits. Fortunately, these domestic speci-

mens are not used in the building industry and the majority

of granites, in both groups, have safe radioactivity level.

The results obtained and compiled in this study expand

the data base on physical properties of industrial granites

and contribute to insight into radiological hazards caused

by granites.

Acknowledgments This work was supported by the Research Fund

of Istanbul University, Project No: 8529/2010. The author thanks

Prof. Dr. Timur Ustaomer and Prof. Dr. Sabah Yılmaz Sahin for their

valuable helps.

Fig. 4 Radioactivity contents of granites produced in Turkey

586 N. Sayın

123

References

Ahmed NK (2005) Measurement of natural radioactivity in building

materials in Qena city Upper Egypt. J Environ Radioact

83:91–99

Amrania D, Tahtat M (2001) Natural radioactivity in Algerian

building materials. Appl Radiat Isot 54:687–689

Anjos RM, Veiga R, Soares T, Santos AMA, Aguiar JG, Frasca

MHBO, Brage JAP, Uzeda D, Mangia L, Facure A, Mosquera B,

Carvalho C, Gomes PRS (2005) Natural radionuclide distribu-

tion in Brazilian commercial granites. Radiat Meas 39:245–253

Beretka J, Mathew PJ (1985) Natural radioactivity of Australian

building materials industrial wastes and by products. Health

Phys 48:87–95

Canbaz B, Cam F, Yaprak G, Candan O (2010) Natural radioactivity

(226Ra, 232Th and 40K) and assessment of radiological hazards in

the Kestanbol granitoid Turkey. Radiat Prot Dosim 141:192–198

Carrera G, Garavaglia M, Magnoni S, Valli G, Vecchi R (1997)

Natural radioactivity and radon exhalation in stony materials.

J Environ Radioact 34:149–159

Cetin E, Altınsoy N, Orgun Y (2012) Natural radioactivity levels of

granites used in Turkey. Radiat Prot Dosim 151:299–305.

doi:10.1093/rpd/ncs007

Doventon JH, Prensky SE (1992) Geological applications of wireline

logs: a synopsis of developments and trends. Log Anal

33:286–303

El-Shershaby A (2002) Study of radioactivity levels in granite of

Gable Gattar II in the north eastern desert of Egypt. Appl Radiat

Isot 57:131–135

Karadeniz O, Cıyrak N, Yaprak G, Akal C (2011) Terrestrial gamma

exposure in the granodiorite area of Bergama (Pergamon)–

Kozak, Turkey. J Radioanal Nucl Chem 288:919–926

Kovler K (2012) Radioactive materials. In: Pacheco-Torgal F, Jalali

S, Fucic A (eds) Toxicity of building materials. Woodhead

Publishing, Cambridge, pp 196–240

Merdanoglu B, Altınsoy N (2006) Radioactivity concentrations and

dose assessment for soil samples from Kestanbol granite area

Turkey. Radiat Prot Dosim 121:399–405

NEA-OECD (1979) Nuclear Energy Agency. Exposure to radiation

from natural radioactivity in building materials. Report by NEA

Group of Experts

Orgun Y, Altınsoy N, Gultekin AH, Karahan G, Celebi N (2005)

Natural radioactivity levels in granitic plutons and groundwaters

in Southeast part of Eskisehir Turkey. Appl Radiat Isot

63:267–275

Orgun Y, Altınsoy N, Sahin SY, Gungor Y, Gultekin AH, Karahan G,

Karacık Z (2007) Natural and anthropogenic radionuclides in

rocks and beach sands from Ezine region Canakkale), Western

Anatolia, Turkey. Appl Radiat Isot 65:739–747

Osmanlıoglu AE (2006) Natural radioactivity and evaluation of

effective dose equivalent of granites in Turkey. Radiat Prot

Dosim 121:325–329

Othman I, Mahrouka M (1994) Radionuclide content in some

building materials in Syria and their indoor gamma dose rate.

Radiat Prot Dosim 59:43–48

Pavlidou S, Koroneos A, Papastefanou C, Christofides G, Stoulos S,

Vavelides M (2006) Natural radioactivity of granites used as

building materials. J Environ Radiact 89:48–60

Rizzoa S, Braib M, Basileb S, Belliac S, Hauser S (2001) Gamma

activity and geochemical features of building materials: estima-

tion of gamma dose rate and indoor radon levels in Sicily. Appl

Radiat Isot 55:259–265

Rogers JJW, Ragland PC (1961) Variation of thorium and uranium in

selected granitic rocks. Geochim Cosmochim Acta 25:99–109

Rybach L (1988) Determination of heat production rate. In: Haenel R,

Rybach L, Stegena L (eds) Handbook of terrestrial heat-flow

density determination. Kluwer, Dordrecht, pp 125–142

Streckeisen AH (1976) To each plutonic rock its proper name. Earth

Sci Rev 12:1–33

Turhan T, Baykan UN, Sen K (2008) Measurement of the natural

radioactivity in building materials used in Ankara and assess-

ment of external doses. J Radiol Prot 28:83–91

Turkmen F, Kun N, Yaprak G (2003) Ulkemizde Uretilen Ve

Amerika-Uzak Dogu Pazarlarında Ilgi Goren Bazı Dogal

Tasların Radyoaktivite Ozellikleri, Turkiye IV. Mermer Sem-

pozyumu (Mersem’ 2003) Bildiriler Kitabi (in Turkish)

Tzortzis M, Haralabos T, Christofides S, Christodoulides G (2003)

Gamma radiation measurements and dose rates in commercially

used natural tiling rocks (granites). J Environ Radioact

70:223–235

UNSCEAR (1993) United Nations Scientific Committee on Effects of

Atomic Radiation Exposure from natural sources of radiation.

UNSCEAR 1993 report to the general assembly, with scientific

annexes, New York, UN

UNSCEAR (2000) United Nations Scientific Committee on the

Effects of Atomic Radiation, United Nations. Sources and effects

of ionizing radiation. UNSCEAR 2000 report to the general

assembly, with scientific annexes. United Nations sales publica-

tion E.00.IX.3, New York, UN

Ustaomer PA, Celebi N, Gungor E, Karahan G, Ersoy S (2005) Dogal

Yapı Malzemelerinden Kaynaklanan 222Rn ve Etkileri. IX.

Ulusal Nukleer Bilimler ve Teknolojileri Kongresi, Izmir, 10

(in Turkish)

Whitfield JM, Rogers JJW, Adams JAS (1959) The relationship

between the petrology and the thorium and uranium contents of

some granitic rocks. Geochim Cosmochim Acta 17:248–271

Granites used as building materials 587

123