Study of Radioactivity in Bajaur Norite Exposed in the Himalayan Tectonic Zone of Northern Pakistan

Abstract

Radioactivity in Granites of Pakistan systematically increases from south to north. The Ambella Granite found at the northern edge of Pakistan is highly radioactive. Radioactivity measurements made on, so called, Bajaur Granite, located in northern Pakistan, have been found to be lowest among all the granitic rock of the area. In order to find out the exact nature of Bajaur rocks, mineralogical studies were carried on rock chips and powdered samples. The Bajaur Norite contains plagioclase feldspar more than 45% as the chief constituent. Orthopyroxene and clinopyroxene are 27% and 18%. Quartz, biotite, and some opaque minerals are also found in accessory amounts. Bajaur Granite is in fact not a granite but Norite, which is rich in Na-Ca plagioclase series of feldspars. The plagioclase feldspar rich in Na-Ca are low in radioactivity. Moreover, the average gamma activities of ${}^{226}$Ra, ${}^{232}$Th, and ${}^{40}$K (4.98 ± 0.13 Bqkg ${}^{-1}$, 4.03 ± 0.31 Bqkg ${}^{-1}$, 204.40 ± 4.72 Bqkg ${}^{-1}$ and a total of all three radionuclides are 214.00 ± 5.39 Bqkg ${}^{-1}$) for Bajaur Norites are found too be much less than the average of the world’s Granites. Indoor and outdoor hazard indices of Bajaur Norite are much below building materials used throughout the world and largely beneath their criterion restrictions. As per radiations’ hazards are concerned, the Bajaur Norite as a building stone may be considered as the safest material available in the area that does not pose any radiological hazard.

1. Introduction

Bajaur is situated close to Mohmand district, Charsadda, Mardan, and Peshawar, which makes its location ideal for trade within the country. Huge reserves of Marble and Granite are found in the Bajaur District, presenting opportunities for value addition in the sector. The Bajaur district boundary matches with Kunar Province of Afghanistan. The length of the border line with Afghanistan is about 52 km long. The land mass lies between 34°30${}^{\prime }$ and 34°58${}^{\prime }$ N latitudes and 71${}^{\prime }$11° and 71${}^{\prime }$48° E longitudes. The Bajaur is located at a distance of about 140 km north of Peshawar.

The Bajaur district is located at a high altitude to the east of the Kunar Valley. The Bajaur district is about 72 km long and 32 km broad close to Kunar Valley, from which it is divided by an unremitting line of rocky frontier hills, establishing a barrier, but it is easily crossable at one or two points. From the ancient times, across this barrier, the old main road ran from Kabul to Pakistan, which passes through the Khyber Pass, Pakistan. The location of the Bajaur district is given in Figure 1.

The Bajaur has severe weather. The winter time starts in November and ends up in March. The winter time is exceptionally cold and freezing; most of the time, the temperature goes below the freezing point. The summer season is very short. It starts from May and ends in October. The Bajaur hottest months extends from June to August. Several springs and streams of fresh water flow all over the region, and it is a potential source for drinking and irrigation. The houses are constructed of mud mostly in the Bajaur area. These houses are usually called Qila in their local language, that is fortresses, which comprises several houses inside. The joint family system is usually prevailing in the Bajaur district.

The deposit site is near the Arkanai village 2 km from Pashat Salarzai and 15 km away from Khar. A road is present to the base of the deposit. Grid references of the deposit are 340°52${}^{\prime }$47.9${}^{″}$ N 710°32${}^{\prime }$08.2${}^{″}$ E, and the elevation of the deposit is 1092 m. General topography of the area is mountainous having a topographic slope of 200–400 WE. Lithology present at the site is in the shape of hillock. There are three mining points working with old low-tech methods in the mining processes. A length of the deposit about 70 m from the west increased to the east, and the width is about 80 m north to south. The panoramic view of Bajaur area is given in Figure 2.

2. Mineralogical Studies of Bajaur Norite

There are various building materials that are being mined in Pakistan. Most of them have been named erroneously as granites. The same is the case for building material exposed in Bajaur in northern Pakistan [2]. Recent radiometric and geological studies have revealed that this is not Granite but a Norite [3]. The Bajaur Norite is very low in radioactivity in contrast to other granites exposed in the area. Stereomicroscopic and petro graphic studies were carried out on a few samples of Bajaur Norite at Geosciences Advance Research Radiation Physics Lab, Park Road, Islamabad, Pakistan. The Bajaur Norite contains plagioclase feldspar more than 45% as the chief constituent. The modal abundance of plagioclase feldspar is 45% orthopyroxene and clinopyroxene are 27% and 18%. Quartz, biotite, and some opaque minerals are also found in an accessory amount. On mineralogical composition it has been named as Norite. Photomicrographs (magnification 25×) are shown below.

3. Material and Methods for Radiological Studies

3.1. Sample Collection and Preparation

To measure the activity of Bajaur granite, which, after study, was determined to be norite, and twenty fresh samples were taken from different sites of Bajaur. Each sample weighs about 1.5 kg. Afterwards, these samples were crushed into the stone jaw crusher (Henan Baichy Machinery Equipment Co., Ltd., Zhengzhou, China). Furthermore, to have a pure sample as per standard operation procedure, the samples were cleaned and washed to remove all impurities in it. To obtain the sample in powder form, the samples were further crushed to 200 $\mathsf{\mu }$ m. These samples were then heated to 230 °F for 16–18 h to minimize the moisture level [4,5]. The samples were then wrapped in polyethylene Marinelli Beaker (Qingdao Sainuo Chemical Co., Ltd., Qingdao, China) [6,7]. After careful preparation of each of these samples, the samples are weighed again. Secular equilibrium must be achieved between 226Ra and 222Rn to have good analysis. For these purposes, the sample and reference material were kept for 40 days in Marinelli Beaker [7].

3.2. Activity Measurements

A High Purity $\gamma$-Ray Spectrometer (HPGe) (DSG Detector Systems GmbH, Mainz, Germany) is used for the radioactivity measurements of the NORMs (Naturally Occurring Radionuclide Material) that is 226Ra, 232Th, and 40K. The gamma spectroscopy is mainly done to evaluate the potential radiological risk for workers or the natural environment [8]. HPGe consists of a hermetically sealed assembly coupled with PC-MCA along with an amplifier. To operate HPGe, liquid nitrogen was introduced in the cooling system of the detector. Details of radionuclides (IAEA Soil-375 source) used for the calibration of detector are given in our previous publication [9]. The efficiency of the system has already been discussed by Younis et al. [10]. All procedures were already described in previous publications [10]. After acquiring secular equilibrium of about 40 days, the samples were evaluated by obtaining a spectrum on HPGe for each sample for a time interval of 15,500 s. The activity concentration of all the samples was calculated by Quindos 1987 with the following formulae [11]:

$$ActivityConcentration(\mathrm{Bq}/\mathrm{kg})=\frac{netcount}{ϵ\ast I_Y\ast T\ast M}$$

(1)

whereas, net counts are equal to the counts under the peak area minus the background peak area. $ϵ$ = At a particular gamma-ray energy, it is an absolute gamma peak efficiency $I_Y$ = decay intensity of the gamma source at specific energy peak T = counting time for the measurement in seconds M = Sample Mass expressed in kg. Activity concentration relating to 226Ra, 232Th, and 40K were estimated from the peaks of their daughter isotopes having various energies. The gamma rays concentration of Radium, Thorium, and Potassium, their total activities are presented in the Bajaur Norite in

Table 1. Ray activities of 226Ra, 232Th, 40K, and their total in the Bajaur Norite. The following abbreviations are used in the table WGA = World GranitesAverages, BMA = Building Material Average.

Sample No	Radium Bq/kg	Thorium Bq/kg	Potassium Bq/kg	Total Bq/kg
1	5.0 5 ± 0.05	3.49 ± 0.57	185.33 ± 5.45	193.87 ± 6.07
2	5.08 ± 0.32	3.62 ± 0.14	212.49 ± 3.74	221.19 ± 4.20
3	4.03 ± 0.1	3.74 ± 0.19	183.29 ± 6.57	191.06 ± 6.86
4	5.19 ± 0.24	4.38 ± 0.27	200.46 ± 11.18	210.03 ± 11.69
5	5.45 ± 0.09	4.61 ± 0.27	251.71 ± 6.31	261.77 ± 6.67
6	4.63 ± 0.10	4.74 ± 0.30	228.81 ± 4.40	238.18 ± 4.80
7	4.3 ± 0.030	4.16 ± 0.82	181.26 ± 3.81	189.72 ± 4.66
8	5.97 ± 0.08	2.21 ± 0.11	103.98 ± 2.49	112.16 ± 2.68
9	8.36 ± 0.26	4.18 ± 0.32	205.73 ± 4.66	218.27 ± 5.24
10	4.09 ± 0.09	3.72 ± 0.33	160.94 ± 9.66	168.75 ± 10.08
11	3.84 ± 0.05	3.75 ± 0.22	149.82 ± 5.45	157.41 ± 5.72
12	4.46 ± 0.17	3.59 ± 0.24	127.26 ± 6.64	135.31 ± 7.05
13	4.38 ± 0.09	3.91 ± 0.19	202.17 ± 2.56	210.46 ± 2.84
14	4.77 ± 0.42	3.29 ± 0.21	162.65 ± 3.68	170.71 ± 4.31
15	5.23 ± 0.10	4.13 ± 0.49	226.05 ± 3.94	235.41 ± 4.53
16	5.28 ± 0.17	5.16 ± 0.45	250.97 ± 3.28	261.41 ± 3.90
17	5.38 ± 0.11	4.96 ± 0.28	363.44 ± 3.15	373.78 ± 3.54
18	5.19 ± 0.09	4.71 ± 0.28	246.83 ± 3.55	256.73 ± 3.92
19	4.82 ± 0.13	4.43 ± 0.40	238.74 ± 2.76	247.99 ± 3.29
20	4.26 ± 0.10	4.50 ± 0.28	217.04 ± 5.52	225.80 ± 5.90
Average	4.98 ± 0.13	4.03 ± 0.31	204.40 ± 4.72	214.00 ± 5.39
WGA	42.00	73.00	1055.00	1170.00 [12]
BMA	50.00	50.00	500.00	600.00

.

4. Results and Discussion

4.1. Gamma-Ray Activities in the Bajaur Norite

The average $\gamma$-ray activity of Radium, in the Bajaur Norite, are 4.98 ± 0.132 Bq per kg (varies from 3.84 ± 0.05 to 8.36 ± 0.26 Bq per kg) that of 232Th is 4.03 ± 0.31 Bq per kg (with a range from 2.21 ± 0.31 to 5.16 ± 0.45 Bq per kg) and of 40K is 204.40 ± 4.72 Bq per kg (which ranges from 130.98 ± 2.68 to 363.44 ± 3.15 Bq per kg). The average of the sum of all $\gamma$-ray activities of Radium+Thorium+Potassium Radionuclides in the Bajaur Norite are 214.00 ± 5.39 Bq per kg. The results are presented in Table 1. The average values of specific activities of Radium, Thorium, and Potassium in the Bajaur Norite are not compatible with the world’s average values of specific gamma rays activities of Radium, Thorium, and Potassium in particular Granites type, which are 42, 73, and 1055 Bq per kg [13]. However, the gamma-ray activities of Radium, Thorium, and Potassium in the Bajaur Norite are comparable to the average of the world’s $\gamma$-ray activities of BMA = Building Material Average (50, 50, and 500 Bq per kg) as per UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation) [12]. All of the values of activity concentration are within the safe limit. Comparable data of current study of specific activity of Radium, Thorium and Potassium in the Bajaur Norite along with several WGA Averages and building materials are shown in Table 1.

4.2. Calculations of Radiological Hazard Indices

The term radiological hazard Exposure is basically related to radiation and their effect on living things. The measurements of radiological hazards and their health effects were usually expressed in hazard indices. The health exposure indices were evaluated by Beretka and Mathew [12,13,14,15]. Health hazards from radiation may arise due to the exposure of radiations either directly or indirectly. In the case of Naturally Occurring Radioactive Material (NORM), these are present naturally in our environment [16]. As humans are exposed to it constantly, the possibility of health hazard risk increases where the concentrations of Uranium ores are greater. The radiation source, if accidentally broken or from direct intake of radioactive materials, will result in severe and immediate health affects in the human body cells. Therefore, the measurement of collective activity of 226Ra, 232Th and 40K in NORMs is very important for the human health. The radiation hazards are further characterized into Indoor and Outdoor Exposure radiations. The indoor hazards further characterize indoor $D_{in}$ and $E_{in}$, etc. Where $D_{in}$ is indoor external dose and $E_{in}$, is Indoor Annual effective dose. The inside harmful quantities are estimated for the houses, kitchens, basements, tombs, mosques, etc. where extensive radioactive material is used. The outdoor hazard indices are calculated for the people living in the deposit area or involved in the mining of the deposits [17]. The outdoor health hazards represent that people are working in the radiation environment or active area and are in danger from radiation effects [18]. These outdoor health hazards include measures like gamma-index, External Dose calculations, annual effective dose, and Excessive life time outdoor cancer risk. Establishing results on the basis of activity calculations of Radium, Thorium, and Potassium for both indoor and outdoor health hazard indicators, the annual effective doses of Bajaur Norite were determined. As it is discussed in detail in our previous publications [10,11], the formulae used for the determination of various health indices in Bajaur Granite are given in

Table 2. Used formulas for the calculation of outdoor and indoor health hazards of Bajaur Norite. * World averages calculated by taking the averages of 226Ra, 232Th, and 40K as 50, 50, and 500 Bq per kg, respectively, in building materials (UNSCEAR) [2,12,15,19,20,21,22].

Indices	Formulae References	* World’s Average of Building Materials	Limit References
Outdoor Hazard Indices
Gamma Index ($I_{\gamma }$)	$\frac{A_{Ra}}{300}+\frac{A_{Th}}{200}+\frac{A_K}{3000}$	0.58	$\le 0.5\approx 0.3{\mathrm{mSvy}}^{-1}$ for Bulk use $\le 2\approx 0.31{\mathrm{mSvy}}^{-1}$ restricted use
Radium Equivalent ($R{a}_{eq}$)	$[\frac{A_{Ra}}{370}+\frac{A_{Th}}{259}+\frac{A_K}{4810}]\times 370$ (Bq/kg)	159.8	370
Outdoor Hazard Index $H_{ou}t$	$\frac{A_{Ra}}{370}+\frac{A_{Th}}{259}+\frac{A_K}{4810}$	0.43	line <1
Outdoor External Dose $D_{out}$	$D_{out}=0.427A_{Ra}+$$0.60462+0.04$ (nGyh ${}^{-1}$)	74.15	51
Outdoor Annual Effective Dose $E_{out}$	$E_{out}=D_{out}\times 8760\times 0.2\times 0.7{\mathrm{SvGy}}^{-1}\times {10}^{-9}$ $E_{out}=D_{out}\times 1.227\times {10}^{-3}{\mathrm{SvGy}}^{-1}$	0.09	1;20 for radiation workers
Outdoor Excessive Life Time Cancer Risk ($ELC{R}_{\left(out\right)}$)	$ELC{R}_{\left(out\right)}=\left(E_{out}\right)\times LE\times RF$ (LE is life expectancy RF is fatal risk factor per Sievert that is 0.05)	$0.32\times {10}^{-3}$	$0.29\times {10}^{-3}$
Indoor Hazard Indices
Alpha Index ($I_{\alpha }$)	$I_{\alpha }=\frac{A_{Ra}}{200}$	0.25	<1
Indoor Hazard Index $H_{in}$	$H_{in}=\frac{A_{Ra}}{185}+\frac{A_{Th}}{259}+\frac{A_K}{4810}$	0.57	<1
Indoor External Dose $D_{in}$	$D_{in}=0.92A_{Ra}+$$1.1A_{Th}+0.081A_K$ (nGyh ${}^{-1}$)	141	55
Indoor Annual Effective Dose $E_{in}$	$E_{in}=D_{in}\times 8760\times$$0.8\times 0.7\times {10}^{-6}$ $E_{in}=D_{in}\times 4.905\times {10}^{-3}$ (mSvy ${}^{-1}$)	0.69	2
Indoor Excessive Life Time Cancer Risk ($ELC{R}_{\left(in\right)}$)	$ELC{R}_{\left(in\right)}=E_{in}\times LE\times RF$ (LE is life expectancy RF is fatal risk factor per Sievert that is 0.05)	$2.42\times {10}^{-3}$	$1.19\times {10}^{-3}$

.

On the basis formulae given in Table 2, the Indoor and Outdoor Radiological Health hazard indices of Bajaur Norite were calculated and presented in

Table 3. Health hazard indices of Bajaur Norite. The first column is sample number while the next five column are Indoor Health Hazard Indices, whereas the last five columns show Outdoor Health Hazard Indices. Furthermore, the following abbreviations are used: WGA = World Granites Averages, BMA = Building Material Averages.

No	${\mathit{I}}_{\mathit{\alpha }}$	${\mathit{D}}_{\mathbf{in}}$	${\mathit{E}}_{\mathbf{in}}$	${\mathit{H}}_{\mathbf{in}}$	${\mathbf{ELCR}}_{\mathbf{in}}$	${\mathbf{Ra}}_{\mathbf{eq}}$	${\mathit{I}}_{\mathit{\gamma }}$	${\mathit{D}}_{\mathbf{out}}$	${\mathit{E}}_{\mathbf{out}}$	${\mathit{H}}_{\mathbf{out}}$	${\mathbf{ELCR}}_{\mathbf{out}}$
1	0.03	23.38	0.11	0.08	0.40	24.36	0.10	12.20	0.01	0.07	0.05
2	0.03	25.65	0.13	0.09	0.44	26.59	0.11	13.39	0.02	0.07	0.06
3	0.02	22.49	0.11	0.07	0.39	23.48	0.09	11.77	0.01	0.06	0.05
4	0.03	25.63	0.13	0.09	0.44	26.87	0.11	13.40	0.02	0.07	0.06
5	0.03	30.18	0.15	0.10	0.52	31.35	0.12	15.77	0.02	0.08	0.07
6	0.02	27.79	0.14	0.09	0.48	29.01	0.12	14.55	0.02	0.08	0.06
7	0.02	23.03	0.11	0.08	0.40	24.19	0.10	12.06	0.01	0.07	0.05
8	0.01	13.48	0.07	0.05	0.23	14.13	0.06	7.04	0.01	0.04	0.03
9	0.04	28.75	0.14	0.10	0.49	30.16	0.12	14.97	0.02	0.08	0.06
10	0.02	20.74	0.10	0.07	0.36	21.79	0.09	10.85	0.01	0.06	0.05
11	0.02	19.65	0.10	0.07	0.34	20.73	0.08	10.29	0.01	0.06	0.04
12	0.02	18.24	0.09	0.06	0.31	19.39	0.08	9.54	0.01	0.05	0.04
13	0.02	24.49	0.12	0.08	0.42	25.50	0.10	12.81	0.02	0.07	0.06
14	0.02	21.02	0.10	0.07	0.36	21.98	0.09	10.97	0.01	0.06	0.05
15	0.03	27.45	0.13	0.09	0.47	28.53	0.11	14.34	0.02	0.08	0.06
16	0.03	30.61	0.15	0.10	0.53	31.96	0.13	16.02	0.02	0.09	0.07
17	0.03	39.47	0.19	0.12	0.68	40.41	0.16	20.63	0.03	0.11	0.09
18	0.03	29.67	0.15	0.10	0.51	30.87	0.12	15.52	0.02	0.08	0.07
19	0.02	28.41	0.14	0.09	0.49	29.51	0.12	14.86	0.02	0.08	0.06
20	0.02	26.24	0.13	0.09	0.45	27.39	0.11	13.74	0.02	0.07	0.06
Average	0.02	25.31	0.2	0.08	0.43	26.41	0.106	13.23	0.016	0.07	0.05
WGA		203.34	1.00	0.07	3.49		0.86	107.49	0.13		0.46
BMA		141	0.69		2.41		0.58	76.05	0.09		1.31
Limits		55	2		2.41		1	51	1		0.70

below.

4.3. Atmosphere and Radon Gas

222Rn is a colorless odorless noble gas which emits in a Uranium series directly into the atmosphere. 226Radium has a half-life of 1600 years which after alpha decay releases radon gas having a half-life of 3.82 days. Radon gas becomes airborne in atmosphere and when inhaled Radon and its daughter progenies like 214Polonium and 218Polonium may stick to the respiratory system of the human beings and may cause lung cancer [23]. Elevated levels of an atmospheric radon level at certain places having high contents of NORMS in rocks and soils have been reported from Karela in India and Brazil, where high cancer cases have been reported [24]. It has been pointed out that radon is released into the atmosphere during the mining and processing of uranium ores. According to (UNSCEAR) (2000), the alpha index and Radium equivalent measured in indoor and outdoor atmosphere indicates that the activity concentration of 222Rn level must not exceed the value of 200 Bqm ${}^{-3}$ in atmosphere [12]. In our study, the radium equivalent is 26.41 Bqkg ${}^{-1}$, which is much less than the recommended value of 200 Bqkg ${}^{-1}$. Moreover, all the outdoor hazards’ indices like outdoor external dose 13.23 nGyh ${}^{-1}$, outdoor Annual effective dose 0.016 mSvy ${}^{-1}$, and outdoor excessive life time cancer risk being 0.05 × 10${}^{-3}$ are all measured values of outdoor radiological Health hazard indices calculated in the outdoor atmosphere are well under the world average for Health hazards. Radon gas from natural sources in building materials accumulate in the atmosphere of buildings and cause lungs cancer [14].

5. Discussion

After comparing the $\gamma$-ray activities of Radium, Thorium, and Potassium in the Bajaur Norite with the World Granite Averages, it is found that Bajaur Granite has mineralogical composition. From the study of the mineralogy department, it is revealed that Bajaur Granite is not Granite but Norite. Therefore, it is not comparable with Granite. The Bajaur Norite is rich in plagioclase feldspars as shown in Figure 3 shown below. Radioactivity is more compatible to potassium. Thus, there is less radioactivity in Na-Ca bearing feldspars. As per plagioclase, mineral data by American Petroleum Institute Units Plagioclase [25,26] are not radioactive.

The activity concentrations of 40K, 226Ra, and 232Th in the Bajaur Norite (4.98 ± 0.13 Bqkg ${}^{-1}$, 4.03 ± 0.31 Bqkg ${}^{-1}$, 204.40 ± 4.72 Bqkg ${}^{-1}$ and total of 214.00 ± 5.39 Bqkg ${}^{-1}$) are much less than the average of world’s Granites (42, 73, 1055 and a total of 226Ra, 232Th, and 40K, which is 1170 Bqkg ${}^{-1}$), and it is also to a lesser extent than the average of the world’s building materials which is (50, 50, and 500 Bqkg ${}^{-1}$). The indoor absorbed dose index (Din) for Bajuar Norite 25.31 nGyh ${}^{-1}$ is smaller than the average of the all over the world Granites range (203.34 nGyh ${}^{-1}$) and below the building material average (141 nGyh ${}^{-1}$), and its threshold value is 55 nGyh ${}^{-1}$. The effective dose indoor ($E_{in}$) of Bajaur Norite is 0.2 mSvy ${}^{-1}$, which is also less than the average of world’s Granites as well as building materials of the world, which have an average value of 0.69 mSvy ${}^{-1}$. The (Ein) of Bajaur Norite is also much lower than the UNSCEAR value of 2 mSvy ${}^{-1}$ [12]. The indoor Excessive Lifetime Cancer Risk (ELCR) (in) is the probability of developing cancer for its lifetime due to absorption of radiations. (ELCR) (in) estimated in current study is (0.43 × 10${}^{-3}$), which is smaller than the value of the cancer occurring possibility (2.41 × 10${}^{-3}$) as per UNSCEAR 2000 [12,27]. As the probability of cancer occurring is much smaller in Norites, this made Bajaur Norite as an ordinary building material, which is not compatible with the activities of the other Granites. The values of gamma index ($I_{\gamma }$) of Bajaur Norite samples are shown in Table 3. The gamma index lies from 0.06 to 0.16 Bqkg ${}^{-1}$ and have a mean of 0.10 Bqkg ${}^{-1}$, which is below the average values of world’s granite and building materials. The gamma index of World’s average of granite is 0.58 Bqkg ${}^{-1}$. According to the limit described by UNSCEAR, a gamma index should be between 1–2 Bqkg ${}^{-1}$, while the gamma index of Bajaur Norite is 0.10 Bqkg ${}^{-1}$, which lies in the safe limit. The $I_{\gamma }$≤ 0.16 amount relates to the gamma index less than 0.3 mSvy ${}^{-1}$. Thus, Bajaur Norite can used as ordinary building material. In Bajaur Norite, the average outdoor absorbed dose (Dout) is 13.23 nGyh ${}^{-1}$ and is much less than the average of 107.49 nGyh ${}^{-1}$ in the world’s Granites and also the world average of 76.05 nGyh ${}^{-1}$ in materials, which is used as materials and below the UNSCEAR 2000 threshold of 51 nGyh ${}^{-1}$ [16]. The amount of the outdoor annual effective dose of Bajaur Norite average is 0.016 mSvy ${}^{-1}$, which remains much lower than WGA of 0.13 mSvy ${}^{-1}$ and is compatible with an WGA limit of 0.09 mSvy ${}^{-1}$ for the building materials and lowers the standard criterion of 1 mSvy ${}^{-1}$. The rare chance of Excessive Life time Cancer Risk ELCR(out) occurring per person in the Bajaur Norite area is limited to 0.05 × 10${}^{-3}$. This is also much smaller than the average of the world’s Granite value (0.46 × 10${}^{-3}$) and hence is much lower than cancer occurrence probability in average value as assessed at the average of the WBA (1.31 × 10${}^{-3}$). Keeping in view of the above statistics of ELCR(out), it is predicted that people living in the Bajaur area have very rare chance of catching cancer due to norite radiation. Furthermore, the feldspar minerals are classified on the basis of their chemical composition being given in Figure 4 also supporting the Norite composition of the stone. Radioactivity measurements of Bajaur Norite reveal that there is not any dangerous aspect of Bajaur Norite being used as a building material, whereas chances of excess lifetime cancer risk due to the natural radiation in Bajaur area are very low.

After measuring all radio hazards’ parameters, the concluding remarks are that Bajaur Norite does not pose any radiological hazard that is dangerous to one’s health. All the indoor and outdoor radiological parameters predict the safety of the Bajaur Norite. All of the values are well below the World Average building materials as well as the average of the world granite level. Summing up the entire study, it is concluded that the Bajuar Norite may be utilized as a basic building material and as an ornamental purpose without any constraints with the radiological hazard point of view.

6. Conclusions

The natural radioactivity of the Bajaur Norite exposed in the Himalayan tectonic zone of Northern Pakistan has been measured. Twenty samples of Norite rocks in Bajaur district have been carefully analyzed using a high resolution HPGe gamma detector. The average gamma activities of 226Ra, 232Th and 40K (4.98 ± 0.13 Bqkg ${}^{-1}$, 4.03 ± 0.31 Bqkg ${}^{-1}$, 204.40 ± 4.72 Bqkg ${}^{-1}$, and a total of 214.00 ± 5.39 Bqkg ${}^{-1}$) for norites are found to be much less than the average of the world’s granites (42 Bqkg ${}^{-1}$, 73 Bqkg ${}^{-1}$, 1055 Bqkg ${}^{-1}$ and a total of 226Ra, 232Th and 40K, which is 1170 Bqkg ${}^{-1}$), and it is also to a lesser extent the average level of these radionuclides’ building materials, which is (50, 50 and 500 Bqkg ${}^{-1}$). Furthermore, all the other health hazard indoor and outdoor indices like Din (25.31 nGyh ${}^{-1}$), Dout (13.23 nGyh ${}^{-1}$), Ein 0.2 mSvy ${}^{-1}$, Eout 0.016 mSvy ${}^{-1}$, ELCR ${}_{in}$ 0.43 × 10${}^{-3}$ and ECRL ${}_{out}$ 0.05 × 10${}^{-3}$ are extensively lower from the average of the world’s building materials and World Granite averages as well as UNSCEAR 2000 recommendation values. In this study, we also reveal that rocks in the Bajaur district are not Granite, but these are Bajaur Norite, with low radioactivity, and are the safest materials available in the area for construction and decoration.