|Year : 2014 | Volume
| Issue : 3 | Page : 132-142
Natural radioactivity concentrations in Alvand granitic rocks in Hamadan, Iran
R Pourimani1, R Ghahri1, MR Zare2
1 Department of Physics, Faculty of Science, Arak University, Arak 38156, Iran
2 Department of Physics, Faculty of Science, Isfahan University, Isfahan 81746, Iran
|Date of Web Publication||10-Apr-2015|
Department of Physics, Faculty of Science, Arak University, Arak 38156
Source of Support: None, Conflict of Interest: None
Natural radioactivity of 30 granite rock samples collected from Alvand plutonic complex was determined using a high-resolution, high purity germanium gamma-spectrometry system. The activity concentrations of 226 Ra, 232 Th and 40 K varied from 8.4 ± 0.6 to 119.3 ± 1.9, i.e., minimum detectable activities (MDA) to 268.4 ± 3.3 and 62.9 ± 4.1 to 1602.6 ± 27.9 Bq/kg, respectively. 137 Cs ranged from MDA to 4.9 ± 0.7 Bq/kg. The radium equivalent activity varies between 35.7 and 624.2 Bq/kg that is lower than the permitted value (370 Bq/kg) except in three samples. The absorbed dose rate ranged from 17.9 to 282.8 nGy/h, and the effective dose rate outdoor was determined to be between 21.9 and 347.0 μSv/y. The annual effective dose rate indoor varied from 87.8 to 1388.2 μSv/y that is lower than the dose criterion, 1 mSv/y, except for PGG(W) and GRG(W) samples. The internal and external hazard indices values range from 0.1-2.0 to 0.1-1.7, respectively, only four out of 30 showed values higher than unity.
Keywords: Alvand, high purity germanium, natural radioactivity, plutonic rocks
|How to cite this article:|
Pourimani R, Ghahri R, Zare M R. Natural radioactivity concentrations in Alvand granitic rocks in Hamadan, Iran. Radiat Prot Environ 2014;37:132-42
|How to cite this URL:|
Pourimani R, Ghahri R, Zare M R. Natural radioactivity concentrations in Alvand granitic rocks in Hamadan, Iran. Radiat Prot Environ [serial online] 2014 [cited 2020 Nov 24];37:132-42. Available from: https://www.rpe.org.in/text.asp?2014/37/3/132/154866
| Introduction|| |
Humans are usually exposed to ionizing radiations. One of the main external sources of irradiation to the human body is represented by gamma radiation (terrestrial environmental background radiation), emitted by natural radioisotopes. Natural environmental radioactivity mainly arises from primordial radionuclides such as uranium-radium ( 238 U- 226 Ra), actinium ( 235 U) and thorium ( 232 Th) series, and the radioactive isotope of potassium ( 40 K) in soils, building materials, water, rocks and atmosphere. These radionuclides have been present in the environment since the formation of the Earth. Another natural source of radiation is cosmic ray that originates from outer space.  Significant amount of artificial radionuclides such as 137 Cs and 90 Sr are also present in the soil resulted by the testing of nuclear weapons in the atmosphere and nuclear accidents such as Chernobyl nuclear power plant in 1986. 
Igneous rocks such as granite contain high quantities of natural radionuclides 226 Ra, 232 Th and 40 K and small quantities are associated with sedimentary rocks. Granitic rocks mainly composed of coarse grains of quartz, K-feldspar, plagioclase and mafic minerals like biotite and amphibole. In addition, there are other common accessory minerals in granites, namely zircon, sphene, apatite and allanite.  Natural radionuclides are present to very insignificant amount in the mantle and the crust of the Earth. Partial melting and fractional crystallization of magma lead to these lithophile elements that can be concentrated in the liquid phase and can be incorporated into the more silica-rich products. , The average of U and Th contents in the Earth's crust has been estimated to be 1.8 and 7.2 ppm and increases from 5 to 15 ppm in granitic composition. Also, the average corresponding radionuclides contents in rocks of basaltic or ultramafic composition has been estimated to be 0.1 and 0.2 ppm respectively.  U and Th-rich minerals are: monazite, allanite, uraninite, thorite, pyrochlore and other lowly radioactive minerals, such as zircon, sphene, and apatite. Major Potassium minerals such as potash feldspars (microcline and orthoclase) and in micas (muscovite and biotite). 
The present work aims to determine the distribution of 226 R, 232 Th, 40 K and 137 Cs of the Alvand plutonic rocks in Hamadan region. In this work, the radium equivalent activity (Ra eq ), the absorbed dose rate in air (D), the annual effective dose rate, the external and internal hazard indices (H ex , H in ) have been computed and compared with the recommended limit. In this way, the level of the background radiation and the effect of radiation on the local population have been assessed. These results are of great interest since granites are commonly used as material for building and ornamental, including indoor covering.
The Alvand plutonic complex (APC) with NW-SE trend located within the major Sanandaj-Sirjan plutonic-metamorphic zone [Figure 1]a]. This zone is an elongated strip with a length of over 1500 km and a width of 150-250 km, has intruded between Zagros belt and central Iran belt.  The APC is placed in western Iran that covered about 400 km 2 in the Hamadan area. It is bounded by latitudes 34°30′ and 34°50′ N and longitudes 48°10′ and 48°40′ E.  Since the Alvand intrusive complex is one of the most important plutonic complexes in Western Iran, during the last years has attracted the attention of many researchers. Alvand plutonic mainly consists of mafic to intermediate rocks, felsic rocks, pegmatite and aplite veins. Felsic magma, which account for the largest volume in this complex, is from rocks such as granodiorite, monzogranite, syenogranite, alkali granite, leucogranite and abundant aplitic and pegmatitic dikes in the region.  Geological map of the APC is shown in [Figure 1]b. 
|Figure 1: (A) The Sanandaj-Sirjan metamorphic Zone in Iran with location of Hamadan complex. (B) Simplified geological map of the Alvand plutonic complex, Hamadan area, western Iran|
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| Materials and methods|| |
Sampling and sample preparation
A total of 30 plutonic rock samples each of mass 2 kg were taken from various localities of APC in Hamadan. Totally, 15 rock samples were collected from the surface of locations in loose formations and 15 rock samples from outcrops, by core method (fresh sample). These samples were collected randomly according to color and texture of the rocks from five different regions Ganjnameh, Darreh-e-Moradbeig, Tarik Darreh, Emamzadeh Kuh and Zaman-abad in the APC. The sampling locations are shown in [Figure 2].
Collected samples were crushed, homogenized and passed through 50-mesh screen changing into fine powder in laboratory.  All samples were packed in standard plastic containers with dimensions of 90 mm diameter and 50 mm height. The collection of samples requires particular care because radon is a short-lived gaseous nuclide and tends to escape from samples. In this work, standard containers with volume 300 cc were sealed. Mass of rock samples was 293 g. After the minimum 50 days of preparing sealed samples, gamma ray spectrometry was carried out. This time is necessary for attaining radioactive equilibrium where the decay rate of the daughters became equal to that of the parent. 
In addition, thin section samples were prepared for microscopic studies to define mineralogical composition of the granite rock samples. The mineralogical results of each sample are summarized in [Table 1].  In [Figure 3], thin section photographs of five plutonic rock samples have been shown (abbreviations from  ).
|Figure 3: Thin section photographs of 5 plutonic rock samples from the Alvand intrusive complex: (a) Illustration of Diorite of Ganjnameh with sphene mineral; (b) illustration of pegmatite of Ganjnameh with apatite and zircon as inclusion in orthoclase; (c) illustration of Biotite granite of DarrehMoradbeig with zircon as inclusions in biotite; (d) illustration of Biotite granite of DarrehMoradbeig with apatite as inclusions in biotite and K-rich minerals (muscovite, biotite and orthoclase); (e) illustration of Monzogranite of Ganjnameh with mica and zircon as inclusion in orthoclase. Qtz: Quartz, Or: Orthoclase, Ms: Muscovite, Zrn: Zircon, Bt: Biotite, Grt: Garnet, Pl: Plagioclase, Amp: Amphibole, Spn: Sphene, Ap: Apatite|
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|Table 1: Minerals composition of the Alvand plutonic rocks (W and F in parenthesis denote to weathered and fresh samples, respectively) |
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Specific activity measurements were performed by high-resolution gamma-ray spectrometry in nuclear physics laboratory ofArak University. Gamma-rays spectrometry was done using a high purity germanium p-type coaxial detector with 38.5% relative efficiency, which is connected to a multi-channel (4096 channels) analyzer. Energy resolution (full width at half maximum) of this detector is 1.98 keV for gamma energy line at 1332.5 keV due 60 Co and a peak-to-compton ratio of 60. Operating voltage was 3000, and the detector and preamplifier are shielded in a chamber of three layers composed of 10 cm thick lead, 1.5 mm thick cadmium and 2.5 mm thick by copper. This shield serves to reduce background radiation. The soft components of cosmic ray, consisting of photons and electrons, are reduced to a very low level by 100 mm of lead shielding. The X-ray (73.9 keV) emitted from lead by its interaction with external radiation is suppressed by cadmium layer and copper layer successively absorbed thermal neutrons produced by cosmic ray.
To minimize the effect of scattering radiation from the shield, the detector was located in the center of the chamber. The samples were placed in the face to face geometry over the detector. Finally, the spectra were registered using Ortec Maestro II software (Tennessee 37831 USA). Each sample is counted over a period of between 62461 and 245653 s to be determined all full-energy peaks of the spectrum and to be perfectly Gaussian shape.
The system was calibrated for energy and efficiency. Point sources 226 Ra and 241 Amused for calibration of the energy and thus the energy range between 59 and 2000 keV can be calibrated. The efficiency calibration was carried out for the standard source including radioisotopes with exactly activity of 241 Am, 109 Cd, 57 Co, 133 Ba, 137 Cs, 60 Co covering an energy range from 59.5 to 1332.5 keV. According to the registered gamma-ray spectra, the absolute efficiency of detectors configuration was computed using the following relation:
Where N i is net counts under the full-energy peak corresponding to the E i energy, Act is radionuclide activity at measured date, P n (E i) is the probability of E i photon emission and t is the counting time. Equation fitted to experimental data by polynomial curve is
Where a (−245488.25), b (11362009), c (−2.3130812 × 10 8 ), d (2.716482 × 10 9 ), e (−2.026204 × 10 10 ), f (9.9420901 × 10 10 ), g (−3.2039674 × 10 11 , h (6.5249987 × 10 11 ), i (−7.5973431 × 10 11 , j (3.836831 × 10 11 ) are constant values, efficiency in % and x is g-ray energy in keV.
Registered gamma-ray spectra were analyzed, and specific activities were calculated using EG&G Ortec OMNIGAM software (Tennessee 37831 USA). In all of the analyzed spectra, correction was done for background gamma-ray measured for empty standard container in the same condition. The activity concentrations of radionuclides in the samples were calculated using the following relation:
Where, NetArea is net count under peak, A Ei is activity concentration in (Bq/kg), E is the efficiency for gamma-ray at energy Ei by detector configuration system, B.R is branching ratio of gamma intensity in %, t is the counting time of spectrum (sec) and m is mass of sample (kg).
The 226 Ra activity concentration of the samples was determined through the intensity of 295.22 and 351.93 keV gamma-rays of 214 Pb and the 609.31, 1120.28 keV of 214 Bi. 232 Th activity concentration was obtained using gamma lines of 228 Ac at 911.2, 968.97 and 338.32 keV. 40 K and 137 Cs were computed using gamma-ray line 1460.7 and 661.66 keV, respectively. Minimum detectable activities (MDA) of the detector are 0.2, 0.5 and 3 Bq for 238 U, 232 Th and 40 K, respectively.
| Results and discussion|| |
The activity concentrations of 226 Ra, 232 Th, 40 K and 137 Cs (in Bq/kg) in the studied samples are presented in [Table 2]. W and F in parenthesis denote to weathered and fresh samples, respectively. The highest activity concentration of 226 Ra and 232 Th were observed in pegmatite sample of Ganjnameh PGG(W) in quantities 119.3 ± 1.9 and 268.4 ± 3.3 Bq/kg, respectively. The highest and lowest activity concentration of 40 K in quantity 62.9 ± 4.1 and 1602.6 ± 28.0 Bq/kg was found in the garnet bearing syenogranite sample GSG(W) and diorite rock DTG(F) of Ganjnameh, respectively. Tourmaline baring pegmatite sample of Zaman-abad PTZ(F) presented the lowest value of 226 Ra activity concentration (8.4 ± 0.6 Bq/kg) while the values of 232 Th activity concentration were found lower than MDA of the measurement system in fresh pegmatite of Zaman-abad PGZ(F) and diorite of Ganjnameh DTG(W) samples.
|Table 2: Activity concentrations of 226Ra, 232Th, 40K and 137Cs (in Bq/kg) of Alvand plutonic rocks |
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Comparison of these results with global average amount shows that the specific activity of 226 Ra for all studied samples is in the same range of the global average (32 Bq/kg) reported by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) (2008) except pegmatite of Ganjnameh PGG(W) and Tourmaline bearing aplite of Emamzade Kuh APE(F) samples.  The specific activity of 232 Th for gabbro-diorite GDD(W), Garnet bearing syenogranite GSG(W), fresh diorite DTG(F), weathered diorite DTG(W), monzodiorite MDG(F), fresh Leucogranite of Ganjnameh LUG(F), Quartz syenite QST(W), Quartz diorite QDE(F), pegmatite PGZ(F) and Tourmaline bearing pegmatite PTZ(F) are less than the global average (45 Bq/kg) reported by UNSCEAR (2008).  On the other hand the zircon mineral wasn't observed in most quoted samples except Quartz syenite QST(F) and Quartz diorite QDE(F) samples, hence it can be resulted that zircon mineral increased the level of the specific activity of thorium in the investigated samples. It seems that the thorium and zircon mineral are similarly but less closely related. Thus, only a part of the total thorium in the studied samples seems to be tied up in zircon mineral. In addition to the highly radioactive zircon, actual thorium minerals are present in the high thorium samples. Such a similar behavior between thorium and zirconia (ZrO 2 ) has been reported by George.  Since the majority of the investigated samples have granitic composition thus show 40 K activity concentrations higher than the global average (412 Bq/kg) reported by UNSCEAR (2008) except gabbro-diorite GDD(W), fresh diorite DTG(F), weathered diorite DTG(W), monzodiorite MDG(F), pegmatite PTZ(F) and Leucogranite (LUA[F], LUT[F], LUG[F], LUD[W], LUG[W] and LUT[W]) samples. Activity concentration of 40 K, less than the global average in Leucogranite samples is in agreement with reported result by Shahbazi et al.  In this paper, the 137 Cs radionuclide observed in some rocks indicates to pollution of this region by fission's fragment due to nuclear accidents in the world transferred by atmospheric process to Iran. The 137 Cs activities in plutonic rock samples of Ganjname, Darreh-e-Moradbeig, Tarik Darreh and Emamzade Kuh varied from MDA −4.9 ± 0.7 Bq/kg, MDA −2.3 ± 0.5 Bq/kg, MDA −1.7 ± 0.7 Bq/kg and MDA −1.0 ± 0.4 Bq/kg. In samples taken from Zaman-abad region, artificial radionuclide 137 Cs was lower than MDA of the measurement system.
[Figure 4] shows specific activity of 226 Ra vs. 232 Th in rock samples. From the results can be understood that the specific activity of 232 Th increases regularly toward the more acidic rocks while the increasing of 226 Ra activity is slight and irregular. Therefore, in this work no observed strong correlation between 226 Ra and 232 Th concentrations. The relative enrichment of thorium may be explained on the basis of oxidation and loss of uranium from magmas during the later stages of their crystallization. Such an explanation assumes that magmas are originally resulted from a relatively homogeneous source. While, different types of sedimentary or other rocks might make granitic magmas with different initial thorium and uranium amounts.  Weathering (for loose rocks collected from the surface of the locations), and hydrothermal alteration processes in secondary reduction of uranium relative to thorium after crystallization of granites are impressive. Hence, 232 Th activity concentration of granite rocks of this work are generally higher than 226 Ra activity concentrations. Such as similar behaviors have been reported by Whitfield et al. and Rogers and Rogland but was not substantiated by Larsen and Gottfried. ,,
|Figure 4: (a) The correlation between activity concentration of 232Th and 226Ra in fresh plutonic rocks. (b) The correlation between activity concentration of 232Th and 226Ra in slightly weathered plutonic rocks|
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The activity concentrations of 226 Ra, 232 Th and 40 K in this work were compared with those from similar investigations in Iran and some countries and summary results are presented in [Table 3]. The results show that the activity concentration of 226 Ra, 232 Th and 40 K for gabbro-diorite of Piranshahr region in Iran are higher than values of those in the present work. In diorite rock, the values of 226 Ra and 232 Th in Egypt and Germany are slightly less than the values in the present work, while activity concentration of 40 K in Egypt and Germany is higher than the values found in the present work. Comparing the results of study of the natural radioactivity in Granodiorite rocks from Mahabad area in Iran, Poland, Um Taghir and Bir El-Sid in Egypt showed that the maximum activity concentration of 226 Ra (140 Bq/kg) belongs to Mahabad area of Iran, which is higher than the values of present work by a factor of 4. The maximum value of 232 Th (248.6Bq/kg) was found in the present work. The maximum activity concentration of 40 K (3739.0 Bq/kg) observed in Um Taghir area in Egypt, which is greater than the values of Tarik Darreh and Ganjnameh regions by a factor of 6 and 4, respectively. Finally, comparison of Granitic samples of present work with similar samples from other countries shows that minimum (min) activity concentration of 226 Ra of present work is higher than min 226 Ra activity concentration of Egypt (eastern desert) and lower than min 226 Ra activity concentration of Iran,  Turkey, Malaysia, Egypt and Yemen. Also, it is similar to the value of Saudi Arabia.  For max 226 Ra activity concentration, the value of the present work is higher than Malaysia and Yemen and lower than other investigated region. Among the 232 Th activity concentrations, while max value of the present work is lower than Turkey, Egypt (eastern desert), it is higher than the others. Also, min 232 Th value in the present work is lower than Iran, Turkey, Egypt (eastern desert), Malaysia, Yemen, Egypt, Saudi Arabia. , For max 40 K activity concentrations, the values of Egypt (eastern desert), Egypt are higher than the value of the present work, and the value of Iran is similar to present work. , Max 40 K activity concentration of the present work is higher than the max 40 K value of Turkey, Malaysia, Saudi Arabia and Yemen.
|Table 3: Activityconcentration (Bq/kg) of Alvand plutonic rocks and other studied |
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Radiological hazard indices
Radium equivalent activity (Ra eq )
Since the distribution of the natural radionuclides are not uniform in the samples under analysis, a radiological index called radium equivalent (Ra eq ) activity has been defined to estimate of the radiation risk associated with these radionuclides. This index is calculated by the following equation
Where, A Ra , A Th and A K are the activity concentration of 226 Ra, 232 Th and 40 K in Bq/kg, respectively.  The Ra eq results for all samples are presented in [Table 4]. The calculated Ra eq ranged from 35.7 ± 1.4 to 624.2 ± 5.5 Bq/kg which are lower than the recommended maximum value of 370 Bq/kg (Berteka and Mathew, 1985) except in pegmatite sample of Ganjnameh PGG(W), Granodiorite of Ganjnameh GRG(W) and Leucogranite of Tarik Darreh which computed 624.2 ± 5.5, 462.4 ± 4.5 and 394.4 ± 4.9 Bq/kg, respectively.
|Table 4: The radium equivalent activity (Bq/kg), absorbed gamma dose rate (nGy/h), annual effective dose rate outdoor (mSv/year), external and internal index of Alvand plutonic rocks |
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In this work, the highest Ra eq activity is found in pegmatite of Ganjname. This sample contains K-rich minerals of biotite, muscovite and high amount of orthoclase and also accessory minerals of zircon, apatite and epidote that contribute to the level of radioactivity of the sample. The gabbro-diorite sample of Darreh-e-Moradbeig with basic composition displays the lowest radioactivity level among all the samples with 49.8 ± 2.7 Bq/kg (after excluding the lowest values for pegmatite and Tourmaline bearing pegmatite samples from Zaman-abad region). This sample consists of the low amount of biotite and also accessory mineral of apatite. Finally, from the general tendency for the plutonic rocks of present work can be resulted that the radioactivity increases from basic to acid rocks except pegmatite and Tourmaline bearing pegmatite samples from Zaman-abad region while shows the lowest of radioactivity level among studied samples. Thus, it is possible that magma sources of quoted samples from Zaman-abad region be different from magma sources of Alvand plutonic rocks. But, no data are available to support this suggestion.
Estimation of the absorbed gamma dose rate and the effective dose rate
According to the formula given by UNSCEAR (2008 ) report, the absorbed gamma radiation dose rate can be estimated outdoor from soil and rocks 1 m above the ground as:
[Table 4] shows the computed outdoor absorbed dose rate varied from 17.9 ± 0.6 to 282.8 ± 2.5 nGy/h.  According to the UNSCEAR reports, the corresponding worldwide average value is 55 nGy/h. , This reveals that the absorbed dose rates in air outdoors for all plutonic rocks except Leucogranite (LUD(W), LUG(F) and LUE(F)), gabbro-diorite GDD(W), diorite (DTG(F), DTG(W)), monzodiorite MDG(F), pegmatite (PZG(F), PTZ(F)) are equal or higher than the worldwide average value.
In order to estimate of the annual effective dose, one has to take into account the conversion factor from absorbed dose in air effective dose and the outdoor occupancy factor or indoor occupancy factor. In the UNSCEAR reports, a value of 0.7 Sv/Gy was used for the conversion factor from absorbed dose in air to effective dose and the outdoor occupancy factor 0.2 (or indoor occupancy factor 0.8).  The effective dose rate outdoor and indoor, in units of μSv/y, was evaluated from the following formulas:
The obtained values for the annual effective dose rates outdoors are presented in [Table 4]. The effective dose rates outdoor of studied samples varied from 21.9 to 347.0 μSv/y. The obtained values are lower than the average annual external effective dose rate of 460 μSv/y.  The results indicate that Alvand mountain can be considered as area with normal natural background radiation. The effective dose indoors estimated according to Eq.(7) for plutonic rocks ranged from 87.8 to 1388.2 μSv/y [Table 4]. It is observed that the effective dose rates exceed the dose criterion set by European Union 1 (EC, 1999) for two granite samples as pegmatite PGG(W) and Granodiorite GRG(W) of Ganjnameh. European Union, states that doses exceeding 1 mSv/y should be taken into account from the radiation protection point of view. Higher doses should be accepted only in some very exceptional cases, where materials are used locally.  Finally, it is concluded that the natural radioactivity levels of plutonic rocks in this work are consistent with their mineralogical composition especially K-feldspar (orthoclase, microcline), micas (biotite and muscovite) and radiogenic accessory minerals (sphene, zircon, apatite and epidote).
External hazard index
The external hazard index due to emitted g-rays of the samples is computed according to the following formula:
Where, A Ra , A Th , A K are the activity concentrations of 226 Ra, 232 Th and 40 K, respectively. The value of H ex should be below the unity for the radiation risk to be negligible. , The values of H ex for the studied granite samples range from 0.1 to 1.7 which for most of samples are less than unity except for PGG(W), GRG(W) and LUG(F) as their values reach1.7, 1.3 and 1.1.
Internal hazard index
Finally, internal hazard index for internal exposure to radon and its short-lived products was estimated by the criterion as:
For the safe use of a material in the construction of dwellings, H in must be lower than unity.  The calculated internal hazard values range from 0.1 to 2.0 [Table 4]. The values of H in for four samples, PGG(W), GRG(W), LUG(F) and APE(F) exceed unity.
| Conclusions|| |
Usually, radiometric study is suggested to provide information on background radioactivity levels and the effect of radiation on the local residents. In present work, the natural radioactivity of the Alvand plutonic rocks in Hamadan have been measured using gamma-ray spectrometry system and the radiological effect have been calculated in some plutonic rocks. The highest activity concentration for 226 Ra and 232 Th are observed in pegmatite rocks of Ganjnameh. Also, the highest activity concentration of 40 K belongs to the Garnet bearing syenogranite sample at the same area Ganjnameh. The values of Ra eq of the studied granite rocks range from 35.7 ± 1.4 to 624.2 ± 5.5 Bq/kg and total absorbed dose ranges from 17.9 ± 0.6 to 282.8 ± 2.5 nGy/h. The annual effective dose rates outdoor and indoor of the studied samples vary from 21.9 to 347.0 μSv/y and 87.8 to 1388.2 μSv/y. It is inferred that the Ra eq values in PGG(W), GRG(W) and LUG(F) are higher than the recommended value, 370 Bq/kg.
The finding of the present work shows that the all examined plutonic rock samples except PGG(W) and GRG(W) are safe for utilization in the construction of dwellings. The results of this study are considered as a baseline data for drawing a radiological map of the area.
| Acknowledgment|| |
This work was funded by the Department of Research of Arak University and authors specially thank of mineralogy laboratory staff of Bu-Ali Sina University of Hamadan.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3], [Table 4]