Health Hazards Assessment and Geochemistry of ElSibai-Abu ElTiyur Granites, Central Eastern Desert, Egypt

: In this paper, a thorough radio- and chem-ecological evaluation of ElSibai-Abu ElTiyur granites located within Egypt’s crystalline basement rocks was conducted for risk and dose assess-ments. Twenty granitic samples from the study area’s various lithological units were analyzed using high-resolution γ -ray spectrometry to determine the natural radioisotopes (U-238, Th-232, and K-40) concentrations. The average concentrations of U-238, Th-232, and K-40 were 38.72, 38.23, and 860.71 Bq/kg, respectively, exceeding the GAV (global average value) documented by UNSCEAR (Scientiﬁc Committee on the Effects of Atomic Radiation, Vienna, Austria). The radiological parameters and indices judging the usage of ElSibai-Abu ElTiyur granites in homes were computed. The obtained results showed that ElSibai-Abu ElTiyur granites are safe to be used by inhabitants as superﬁcial building materials, as per the globally accepted values and the recommended safety limits approved by UNSEAR, WHO (World Health Organization, Geneva, Switzerland), ICRP (Interna-tional Commission on Radiological Protection, Ottawa, ON, Canada), and EC (European Commission, Luxembourg). Further, the samples were subjected to ICP-MS (inductively coupled plasma mass spectrometry) analysis for quantifying radionuclide variations with chemical composition. Geochemically based on the ICP-MS results, the studied granites proved to be highly evolved A-type granites. They span the metaluminous to peralkaline ﬁelds. The REE patterns are characterized by the enrichment of the light rare earths (LREE) over the heavy ones (HREE) where (La/Yb) n = 5.2, (Gd/Yb) n = 1.63 with pronounced negative Eu-anomalies (Eu/Eu*) n = 0.49. The albite granite exhibits the highest concentrations of Ga, Nb, Ta, U, and Y, and REE (Gd, Dy, Ho, Yb) than the Na-metasomatic granites. Finally, the obtained data serve as a valuable future database for ﬁnding out the compatibility of the geochemical data with the natural radioactivity levels of granites. recommended that controls should be based on a dose range from 0.3–1 mSv y In light of this approach, all current increments of the YEGD originating from the granites under investigation ﬂuctuated in the exemption level (Figure 10), denoting that the granites under consideration can be safely used as superﬁcial building materials.


Introduction
Uranium and thorium are constant components of most minerals. The average content of these elements in the earth's crust is 2 ppm for uranium and 12 ppm for thorium. A distinctive feature of the uranium ion is its ability to rapidly oxidize and convert to uranyl (U 6+ ). Hexavalent uranium can easily combine with oxygen and interact in complex compounds with carbonates, sulphates, and fluorides. In addition, it has the ability to precipitate in rocks containing reducing substances [1].
Many varieties of igneous rocks are particularly rich in uranium. The latter is concentrated in rocks containing SiO 2 and alkalis (Na 2 O and K 2 O). The radionuclides, mentioned above, cause lung cancer by damaging the chromosome. In addition, uranium causes disorders in kidney functioning [2].

Gamma Spectrometric Analysis
The collected samples were crushed into a fine powder using a jaw crusher then sieved by a 200 μm mesh screen. All samples were dried at a temperature of 110 °C. Each sample had been weighted and transferred into an airtight cylindrical plastic container (47.6 mm radius, 82 mm height, and 0.5 mm thickness). Finally, the samples were saved for four weeks towards a secular equilibrium action between parents and their short-lived progenies in natural decay chains.
The gamma spectral analyses were performed using a coaxial Canberra HPGe detector (GR4020). The detector is characterized by a relative efficiency (40%) for 3″ × 3″ NaI (Tl) crystal and energy resolution (2 keV) for the 1332 keV Cobalt-60 γ-line. Moreover, it operates with a suitable lead shield (Model 747E, preventing more than 98% of the background noise). The radioisotopes concentration (terrestrial radioisotopes) for each sample were determined in Bq/kg using their counting spectrums, the latter were obtained and analyzed using Genie-2000 software.
Before starting the measurement, the system was calibrated for energy and efficiency. The energy calibration was carried out by acquiring spectra from standards sources of known energies such as 60 Co (1.332 MeV and 1.172 MeV). For the efficiency calibration, ISOCS/Lab-SOCS Canberra's Geometry Composer software (as a part of Genie-2000 software and based on the Monte Carlo Simulation) was used instead of the standard source. This was done individually for each sample to insert the geometry dimensions optimally and improve the efficiency of the HPGe detector.
The sample measuring time (counting spectrum) was approximately in the range between 8 to 24 h. The gamma-ray photopeaks corresponding to 1.4608 MeV ( 40 K) were taken into account to compute 40

Gamma Spectrometric Analysis
The collected samples were crushed into a fine powder using a jaw crusher then sieved by a 200 µm mesh screen. All samples were dried at a temperature of 110 • C. Each sample had been weighted and transferred into an airtight cylindrical plastic container (47.6 mm radius, 82 mm height, and 0.5 mm thickness). Finally, the samples were saved for four weeks towards a secular equilibrium action between parents and their short-lived progenies in natural decay chains.
The gamma spectral analyses were performed using a coaxial Canberra HPGe detector (GR4020). The detector is characterized by a relative efficiency (40%) for 3" × 3" NaI (Tl) crystal and energy resolution (2 keV) for the 1332 keV Cobalt-60 γ-line. Moreover, it operates with a suitable lead shield (Model 747E, preventing more than 98% of the background noise). The radioisotopes concentration (terrestrial radioisotopes) for each sample were determined in Bq/kg using their counting spectrums, the latter were obtained and analyzed using Genie-2000 software.
Before starting the measurement, the system was calibrated for energy and efficiency. The energy calibration was carried out by acquiring spectra from standards sources of known energies such as 60 Co (1.332 MeV and 1.172 MeV). For the efficiency calibration, ISOCS/Lab-SOCS Canberra's Geometry Composer software (as a part of Genie-2000 software and based on the Monte Carlo Simulation) was used instead of the standard source. This was done individually for each sample to insert the geometry dimensions optimally and improve the efficiency of the HPGe detector.
The sample measuring time (counting spectrum) was approximately in the range between 8 to 24 h. The gamma-ray photopeaks corresponding to 1.4608 MeV ( 40 K) were taken into account to compute 40  The activity concentration AC E i for the radioactive daughter of the radioisotope of interest ( 40 K, 238 U, and 232 Th) can be estimated from its corresponding energy peak E i via the following equation: where N Ei , γ Ei , and ε Ei are the net peak count, the γ-decay transition probability, and the detector efficiency at energy E i , respectively, t is the sample measuring time and M s is the sample mass in kg. Hence the specific activity AC j in Bq/kg of jth parent ( 238 U, 232 Th, and 40 K) having a number n of detected daughters' photopeaks, is obtained by: The AC U , AC Th , and AC K were used to express the specific activity concentrations of 238 U ( 226 Ra), 232 Th, and 40 K radioisotopes, respectively. 226 Ra being the highest radiological significance in the disintegration chain of 238 U is considered an alternative for 238U [19,20].

Geochemical Analysis
To confirm the gamma spectrometric analysis results and characterize the ElSibai-Abu ElTiyur granite from the chemical point of view, eight samples were analyzed for whole-rock major and trace elements composition at OMAC lab (Loughrea, Ireland). The concentrations of trace elements including Uranium (U), Thorium (Th), and rare-earth elements (REE), were detected using lithium borate fusion digestion and ICP-MS (ALS code ME-MS81). For the concentrations of the elements Ag, As, Cd, Co, Cu, Li, Mo, Ni, Pb, Sc, Tl, and Zn, the four-acid digestion method and ICP-AES (ALS code ME-4ACD81) were used. The concentrations of the major and minor oxides, including K 2 O, were measured through lithium borate fusion digestion and ICP-AES (ALS code ME-ICP06). More detailed information on the analytical techniques and preparations at the OMAC lab are available at (www.alsglobal.com, accessed on 30 November 2021).
The U and Th elemental concentrations from the ICP-MS technique were given in ppm, whereas the K concentration obtained from K 2 O via the ICP-AES analysis, was in percent (%). Consequently, the specific activity concentrations in Bq/kg of 232 Th, 238 U, and 40 K were computed as reported previously by El-Gamal et al. [9].

Activity Concentrations of the Radioisotopes
The activity concentrations (Table 1) reported herein and used to assess the health hazards of the studied granites, are those obtained from the HPGe detector technique, while those from the ICP-MS analysis are used to confirm the results. Correlations between the concentrations of 238 U, 232 Th, and 40 K obtained from the above-mentioned two techniques are shown in Figure 2. The radionuclides concentration values are highly consistent in both techniques with Pearson correlation coefficients of 0.929, 0.968, and 0.857 for 238 U, 232 Th, and 40 K, respectively. Furthermore, the mean values obtained for both 238 U and 232 Th concentration slightly more than GAVs of these radionuclides in regular soil, namely 35 and 30 for 238 U and 232 Th, respectively [21], but they do not surpass their values in building rials, namely 50 and 50 Bq/kg for 238 U and 232 Th [22], Table 1 and Figure 3. While the concentration of 40 K increases by a factor of 2.15 and 1.72 when compared to their (400 and 500 B/kg as documented by UNSCEAR [21] and UNSCEAR [22]) in regul and building materials, respectively (Table 1 and Figure 4). This result shows the su ity of the ElSibai-Abu ElTiyur granites for use as building materials in dwellings.  S1  S2  S3  S4  S5  S6  S7  S8 S9 S10 S11 S12 S13 S14 S15 S16 S17 S18 S19 S20 AV  Furthermore, the mean values obtained for both 238 U and 232 Th concentration slightly more than GAVs of these radionuclides in regular soil, namely 35 and 30 for 238 U and 232 Th, respectively [21], but they do not surpass their values in building rials, namely 50 and 50 Bq/kg for 238 U and 232 Th [22], Table 1 and Figure 3. While the concentration of 40 K increases by a factor of 2.15 and 1.72 when compared to their G (400 and 500 B/kg as documented by UNSCEAR [21] and UNSCEAR [22]) in regula and building materials, respectively (Table 1 and Figure 4). This result shows the su ity of the ElSibai-Abu ElTiyur granites for use as building materials in dwellings. 110 120 S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11 S12 S13 S14 S15 S16 S17 S18 S19 S20 AV    S9 S10 S11 S12 S13 S14 S15 S16 S17 S18 S19 S20 AV Furthermore, the mean values obtained for both 238 U and 232 Th concentrations are slightly more than GAVs of these radionuclides in regular soil, namely 35 and 30 Bq/kg for 238 U and 232 Th, respectively [21], but they do not surpass their values in building materials, namely 50 and 50 Bq/kg for 238 U and 232 Th [22], Table 1 and Figure 3. While the mean concentration of 40 K increases by a factor of 2.15 and 1.72 when compared to their GAVs (400 and 500 B/kg as documented by UNSCEAR [21] and UNSCEAR [22]) in regular soil and building materials, respectively (Table 1 and Figure 4). This result shows the suitability of the ElSibai-Abu ElTiyur granites for use as building materials in dwellings.  Table 2 and Figure 5 show the results of the natural radioactivity levels of the investigated granites versus the previous studies on Egyptian granites as well as on those from other countries. The normalization for radionuclides concentrations values of 226 Ra ( 238 U), 232 Th, and 40 K from previous studies was carried out by the values of the current work ( Figure 5). It is found that the radioisotopes concentrations for 238 U and 232 Th for ElSibai-Abu ElTiyur granitic samples are smaller than those reported from most of the previous literature (Table 2 and Figure 5), reflecting their safe use as tiling materials in dwellings.

Geochemical Characterization
The chemical composition of representative granitic samples from ElSibai-A
(Symbols as in a).
In all studied rocks, thorium and uranium were found. The highest concentrations were found in samples S1, S13, S14, and S15 (Table S1). The main carriers of thorium and uranium in the rocks under investigation are the accessory minerals (zircon, apatite, and fluorite).
In all studied rocks, thorium and uranium were found. The highest concentrations were found in samples S1, S13, S14, and S15 (Table S1). The main carriers of thorium and uranium in the rocks under investigation are the accessory minerals (zircon, apatite, and fluorite).
Chondrite-normalized REE patterns for the alkaline granites and the albitized granite (sample S1) are presented in Figure 6d. The alkaline granites show enrichment in the REE (∑ REE average 285 ppm). They exhibit parallel to subparallel patterns. They are characterized by the enrichment of LREE over the HREE where the average (La/Sm) n is 2.33 and (Gd/Yb) n = 1.56. The ratio of (La/Yb) n is 4.77 (average) reflecting the fractionated nature of ElSibai-Abu ElTiyur alkaline granites. They manifest a moderate negative Eu anomaly where Eu/Eu* ranges from 0.16 to 0.63 (average 0.44). These REE patterns are consistent with the patterns of the alkaline A-type granites worldwide [54,55]. The REE pattern of the albitized granite (La/Yb) n = 1.54) is the most enriched in HREE relative to the LREE, showing the least negative Eu-anomaly (Eu/Eu* = 0.16). This HREE enrichment parallels those of Na, Nb, Ga, U, Ta, and Y (sample S1 in Table S1), most likely related to the late-stage processes of albitization and fluorine reaction [56].
The correlation coefficients for the major oxides and trace elements including U, Th, and REEs, were calculated for the ElSibai-Abu ElTiyur granites (Table S2 in Supplementary Material). As per Evans [57], the Pearson correlation coefficient is weak (0.20-0.39), moderate (0.40-0.59), strong (0.60-0.79), and very strong (0.80-1.00). According to the correlation matrix, all the interesting elements showed strong (>0.65) to very strong (>0.8) positive correlations with each other. LREEs and HREEs exhibit a good association with the incompatible elements. Uranium is strongly associated with SiO 2 , Rb, and Th in rockforming minerals, while thorium is highly linked to the elements Cs, Li, Pb, and Rb in the mineralogical phases.
All the samples of ElSibai-Abu ElTiyur granites plot in the A-type granite field [44], using the standard tectonic discrimination diagram (Figure 6f). They occupy the A2 field or OIB Ocean island setting (Figure 6g) on the Nb-Y-Ga*3 ternary diagram (Eby [45]). They were emplaced in a within-plate setting (Figure 6h) [46], except for the two alkaline samples (S7 and S9) which experienced further fractionation, falling in the volcanic arc setting. We believe that they were emplaced with the opening of the Red Sea. The ratio Y/Nb varied between 0.75 and 2.26, i.e., they are derived from sources chemically similar to those of oceanic island basalts, while those with Y/Nb > 1.2 are derived from sources chemically similar to island arc or continental margin basalts. From all the above, we suggest that many processes including fractionation from mantle-derived basaltic magmas, during the phase of fracturing and crustal fading, following the termination of the Pan-African orogeny generated the granites of ElSibai-Abu ElTiyur.

Potential Health Hazards Assessment
All over the world, granites are used in dwellings and in construction works. To utilize safely these granites as a natural resource, the possible radiological risks that may have originated from the contained radioisotopes must be determined. Herein, several radiological indices and dosages were computed to estimate the radiological effects originated by ElSibai-Abu ElTiyur granites when used in dwellings compared with the global standards (Table 3). Radium equivalent index in Bq/kg is a widely used radiological hazard index. It is a convenient index to compare the specific activities of rock samples containing different amounts of 238 U, 232 Th, and 40 K. It is presented by Beretka et al. [62] as Equation (3) on the assumption that the same gamma dose rate was produced from 370 Bq/kg of U-238 or 259 Bq/kg of Th-232 or 4810 Bq/kg of K-40.
Ra eq [Bq/kg] = AC U + 1.43AC Th + 0.077AC K For safe use, Ra eq levels in granites should not outweigh the allowable limit (370 Bq/kg), equivalent to a 1.5 mSv effective dose per year [58].
The calculated Ra eq values of all studied samples were listed (Table 4) and plotted ( Figure 7). It is clear that the samples of ElSibae-Abu ElTiyur granites have Ra eq values lying between 112.48-238.25 Bq/kg (avg. value 159.66 ± 8.15 Bq/kg), i.e., not exceeding the adopted value (370 Bq/kg).

Gamma and Alpha Indices (Iγ and Iα)
Alpha and gamma indices (Iα and Iγ) as radiological parameters, can the population living in standard massive granitic walls rooms and wor mines with good ventilation [63].
The gamma index (Iγ) for building materials resulting in external gam [20] of a dose boundary of 1 mSv/y is computed as follows: AC AC AC  S2  S3  S4  S5  S6  S7  S8 S9 S10 S11 S12 S13 S14 S15 S16 S17 S18 S19 S20 AV  Alpha and gamma indices (I α and I γ ) as radiological parameters, can be applied to the population living in standard massive granitic walls rooms and workers in granite mines with good ventilation [63].
The gamma index (I γ ) for building materials resulting in external gamma irradiation [20] of a dose boundary of 1 mSv/y is computed as follows: As per the European Commission European Commission [20], the yearly effective gamma dose (YEGD) rates originate from building materials used in floors and surfaces (granites and other materials) of limited use (ornamental). If I γ ≤ 2, it meets an increase in the YEGD dose ≤ 0.3 mSv/y (exemption level of building materials from all limitations about their radioactivity), when 2 < I γ ≤ 6 means it matches the YEGD ≤ 1 mSv/y (recommended action level).
Concerning the characterization of the excess alpha radiation exhaled from granite (as a building material in dwellings), the alpha index (I α ) has been calculated [63] using the following equation: The alpha index (I α ) reflects the concentration of 226 Ra activity that should not be more than 200 Bq/kg, otherwise will lead to health risks. AC Ra should be less than or equal to 200 Bq/kg, i.e., the suggested activity limit for 226 Ra in the appropriate building material (I α ≤ 1) by ICRP and European Commission [9,58,60].
The mean value of the gamma index (I γ ) for the examined samples exceeds the alpha index (I α ) by a factor of three ( Figure 8 and Table 4). The values of I γ of all samples examined were less than 1. Similarly, the alpha index values did not outstrip 1, thus, these indices meet internal and external radiological recommendations (Table 3). Therefore, ElSibai-Abu ElTiyur granites could be used as surface building materials without any limitations.

Absorbed Gamma Dose Rate (AGDR)
Estimation of the excess absorbed gamma dose rate indoors caused b terials (increment to that of outdoors) relies essentially upon: (1) the concen radioisotopes ( 238 U, 232 Th, and 40 K), (2) the properties of these materials, ways in dwellings [64]. As indicated by the European Commission Europea [20], the extra AGDR (in nGy h −1 ) in the air within a room, owing to using superficial construction materials in its walls and floor, can be determined u

Absorbed Gamma Dose Rate (AGDR)
Estimation of the excess absorbed gamma dose rate indoors caused by building materials (increment to that of outdoors) relies essentially upon: (1) the concentrations of the radioisotopes ( 238 U, 232 Th, and 40 K), (2) the properties of these materials, and (3) design ways in dwellings [64]. As indicated by the European Commission [20], the extra AGDR (in nGy h −1 ) in the air within a room, owing to using the granite as superficial construction materials in its walls and floor, can be determined using the Equation (6) [28,65]: Notably, the coefficients 0.12, 0.14, and 0.0096 in nGy h −1 /Bq/kg included in Equation (6) are estimated according to the model of the standard room dimension (4 m × 5m × 2.8 m) designed by rectangular walls of concrete (20 cm in thickness and 2350 kg/m −3 in density) and tiled with superficial material (3 cm thickness and 2600 kg/m 3 density) in walls and floor.
The calculated values of the excess AGDR indoor originating from ElSibai-Abu ElTiyur granitic samples, when used as superficial building materials are given (Table 4) and compared to the recommended GAVs ( Figure 9). They fluctuate between 13.09 to 26.72 nGy h −1 with a mean of 18.26 ± 0.89 nGy h −1 , which is less than their corresponding GAVs of 84 and 70 nGy h −1 indoors UNSCEAR [21] and the European Commission European Commission [20], respectively (Table 4 and Figure 9). radioisotopes ( 238 U, 232 Th, and 40 K), (2) the properties of these materials, ways in dwellings [64]. As indicated by the European Commission Europe [20], the extra AGDR (in nGy h −1 ) in the air within a room, owing to usin superficial construction materials in its walls and floor, can be determined tion (6) [28,65]: Notably, the coefficients 0.12, 0.14, and 0.0096 in nGy h −1 /Bq/kg includ (6) are estimated according to the model of the standard room dimension m) designed by rectangular walls of concrete (20 cm in thickness and 2350 sity) and tiled with superficial material (3 cm thickness and 2600 kg/m 3 d and floor. The calculated values of the excess AGDR indoor originating from El yur granitic samples, when used as superficial building materials are give compared to the recommended GAVs ( Figure 9). They fluctuate betwee nGy h −1 with a mean of 18.26 ± 0.89 nGy h −1 , which is less than their corres of 84 and 70 nGy h −1 indoors UNSCEAR [21] and the European Commi Commission [20], respectively (Table 4 and Figure 9).  S2 S3 S4 S5 S6 S7 S8 S9 S10 S11 S12 S13 S14 S15 S16 S17 S18 S19 S20 AV

GAV of AGDR as in UNSCEAR
GAV of AGDR as in E.C.

Yearly Effective Gamma Dose (YEGD)
Based on the excess AGDR computed from Equation (7), the indoor yearly effective gamma dose increment (YEGD) in mSv y −1 to individuals in general society (the normal individuals invest 80% of their days indoors) has been estimated by Equation (9) as follows [20,21]: where 0.8, 0.7 Sv Gy −1 , 8766 h, and 10 −6 are the indoor occupancy factor, conversion coefficient from the absorbed dose in the air to the effective dose, yearly hours number, transformation number from nano to milli, respectively. The computed increments in the YEGD rates owing to the usage of ElSibae-Abu ElTiyur granitic samples as superficial materials indoors are illustrated in Table 4 and Figure 10. European Commission European Commission [20] reported that "building materials should be exempted from all restrictions concerning their radioactivity if the excess gamma radiation originating from them excel the annual effective dose of a member of the public by 0.3 mSv, at most. It is, therefore, recommended that controls should be based on a dose range from 0.3-1 mSv y −1 ". In light of this approach, all current increments of the YEGD originating from the granites under investigation fluctuated in the exemption level ( Figure 10), denoting that the granites under consideration can be safely used as superficial building materials.
formation number from nano to milli, respectively. The computed increments YEGD rates owing to the usage of ElSibae-Abu ElTiyur granitic samples as sup materials indoors are illustrated in Table 4 and Figure 10. European Comm European Commission [20] reported that "building materials should be exempted all restrictions concerning their radioactivity if the excess gamma radiation origi from them excel the annual effective dose of a member of the public by 0.3 mSv, a It is, therefore, recommended that controls should be based on a dose range from mSv y −1 ". In light of this approach, all current increments of the YEGD originatin the granites under investigation fluctuated in the exemption level ( Figure 10), de that the granites under consideration can be safely used as superficial building ma Figure 10. YEGD values variation in the investigated samples.

Excess Lifetime Cancer Risk (ELCR)
The ELCR is an essential radiological risk assessment parameter because it p a person's probability of acquiring cancer due to low-dose radiation exposures dur lifetime. Using Equation (8), the ELCR is attributable to the effective gamma dose incurred yearly indoors due to the use of granite as superficial materials is calculate
The values of ELCR originating from the studied granitic samples, when used perficial material (Table 4)

Excess Lifetime Cancer Risk (ELCR)
The ELCR is an essential radiological risk assessment parameter because it predicts a person's probability of acquiring cancer due to low-dose radiation exposures during his lifetime. Using Equation (8), the ELCR is attributable to the effective gamma dose excess incurred yearly indoors due to the use of granite as superficial materials is calculated [66].
where ALE and RF are the life average expectancy (66 years) [19] and risk fatal for stochastic impact (0.05 Sv −1 for the overall population), respectively [67]. The values of ELCR originating from the studied granitic samples, when used as superficial material (Table 4) are plotted against their global average values originating outdoors and indoors ( Figure 11). It is clear that the values of the indoor ELCR originating from ElSibai-Abu ElTiyur granites are scattered near and around the line representing the ELCR global average values outdoors 0.29 × 10 −3 (arising from gamma dose rate outdoor as background calculated according to UNSCEAR) [68], as well as having a mean value of 0.3 × 10 −3 (approximately on the line). This mean value of ELCR (0.3 × 10 −3 ) is smaller by a factor of 4 than its corresponding indoor global average of ELCR (1.16 × 10 −3 arising from gamma dose rate indoor due to only walls, floor, and ceiling Qureshi et al. [69]). The indoor global average value of ELCR (1.16 × 10 −3 ) Qureshi et al. [69], is calculated for a typical room with concrete walls, floor, and ceiling having the following activity concentrations 50, 50, and 500 Bq/kg for 226 Ra, 232 Th, and 40 K, respectively. According to the ELCR increment (being 0.3 × 10 −3 ) for the rock samples under investigation, in addition to what was reported by Mohammed et al. [68]: "equivalent values of ELCR equal to 1, 10, 100, and 1000 mSv/y will cause a mortal cancer of 0.004, 0.04, 0.4, and 4%, respectively". Accordingly, cancer risk possibility, in a lifespan, due to the usage of ElSibai-Abu ElTiyur granites as superficial material, is still insignificant to indoor ELCR. ment (being 0.3 × 10 −3 ) for the rock samples under investigation, in additio reported by Mohammed et al. [68]: "equivalent values of ELCR equal to 1000 mSv/y will cause a mortal cancer of 0.004, 0.04, 0.4, and 4%, respecti ingly, cancer risk possibility, in a lifespan, due to the usage of ElSibai-Abu E as superficial material, is still insignificant to indoor ELCR.

Indoor Radon Exhalation and Concentration
As a result of radium ( 226 Ra) disintegration of soils, rocks, and their struction materials), radon ( 222 Rn) is generated and flows through their po [31]. The biggest annual radiation dose incurred by people arises from rad spring in the air. Lung cancer probability can largely increase as a result o dose for the long term, especially in dwellings. Hence, it is important to e tivity concentration and the exhalation rate of indoor radon.

Indoor Radon Exhalation and Concentration
As a result of radium ( 226 Ra) disintegration of soils, rocks, and their products (construction materials), radon ( 222 Rn) is generated and flows through their pores into the air [31]. The biggest annual radiation dose incurred by people arises from radon and its offspring in the air. Lung cancer probability can largely increase as a result of incurring this dose for the long term, especially in dwellings. Hence, it is important to estimate the activity concentration and the exhalation rate of indoor radon.
According to the theoretical evaluation of radon exhalation rate in Equation (9), the indoor radon concentration (IRC) in Bq/m 3 was calculated as follows [28,63]: where S (in m 2 ), V (in m 3 ), and λ o (in h −1 ) are the surface area exhaled radon, room air volume, rate of air removal by ventilation, respectively. In this work, the worst cases were considered, where the removal rate by poor ventilation (λ o = 0.1 h −1 ) and emanation coefficient value (η = 0.45) were taken [28,63,73]. Moreover, furniture occupancy has been taken into consideration, consequently, the value of 2 m −1 for the proportion S/V in the above equation has been taken [28].
The computed radon exhalation rate values (RER) for the investigated granitic samples of ElSibai-Um ElTiyur (Table 4 and (Table 4 and Figure 12). This average is above the world average (40 Bq m −3 ) (UNSCEAR [21], but still below the permissible range (100 to 300 Bq m −3 ) as recommended by the World Health Organization (WHO) [60] ( Figure 12). This is quite clear, where 60% of the samples fulfills IRC < 100 Bq m −3 formula, while the remaining 40%, 100 < IRC < 300 Bq m −3 (Table 4). This mean value of indoor radon concentrations (IRC) is below the recommended limit of 200 Bq m −3 (European Commission European Commission [20] and ICRP [61]. Accordingly, the population exposure is unaffected significantly by radon emission from ElSibai-Abu ElTiyur granites if they are employed as tiles in residences. where S (in m 2 ), V (in m 3 ), and λo (in h −1 ) are the surface area exhaled radon, volume, rate of air removal by ventilation, respectively. In this work, the worst ca considered, where the removal rate by poor ventilation (λo = 0.1 h −1 ) and emanat ficient value (η = 0.45) were taken [28,63,73]. Moreover, furniture occupancy h taken into consideration, consequently, the value of 2 m −1 for the proportion S/ above equation has been taken [28].
The computed radon exhalation rate values (RER) for the investigated gran ples of ElSibai-Um ElTiyur (Table 4 and Figure 12) (Table 4 and Figure 12). This average is above th average (40 Bq m −3 ) (UNSCEAR [21], but still below the permissible range (100 t m −3 ) as recommended by the World Health Organization (WHO) [60] (Figure 12 quite clear, where 60% of the samples fulfills IRC < 100 Bq m −3 formula, while the ing 40%, 100 < IRC < 300 Bq m −3 (Table 4). This mean value of indoor radon concen (IRC) is below the recommended limit of 200 Bq m −3 (European Commission E Commission [20] and ICRP [61]. Accordingly, the population exposure is unaffe nificantly by radon emission from ElSibai-Abu ElTiyur granites if they are emp tiles in residences.  [31,73]. The values of the IYEDRn (Table 4 and Figure 13) of the measured samples fl between 1.06 to 4.51 mSv/y with an average value of 2.42 ± 0.21 mSv/y, i.e., hig the worldwide average (1.2 mSv/y) provided by UNSCEAR [21]. However, th values for 30% of the considered samples lie within the (R.A.L.) recommended act (3-10 mSv/y) stated in ICRP [61], while the remaining 70% are less than this leve 13). As a result, ElSibai-Abu ElTiyur granites do not cause possible risks to the pop S2 S3 S4 S5 S6 S7 S8 S9 S10 S11 S12 S13 S14 S15 S16 S17 S18 S19 S20 Av The IYED Rn in mSv y −1 incurred by the populations owing to the IRC is computed through the model presented in UNSCEAR [73] is as follows:

Data Statistical Analysis
The current data was statistically analyzed using both the Origin Pro SPSS statistics (version 23) software packages. The numerical and graphi tracted from the statistical analysis were used for investigating the normal of radioisotope concentrations and radiological parameters. Descriptive st plifying data by reducing it into a simple summary were performed. The tistics calculated include the minimum (Min), maximum (Max), mean, r standard deviation, kurtosis, and skewness ( Table 5). The histogram tog frequency distribution curve were determined and compared with the fun distribution using the Shapiro-Wilk and Anderson-Darling tests (p-value tionally, the potential linear relationships among variables were also sta duced herein via Pearson correlations analysis. For all variables (Table 5), standard deviations that are less than the a high degree of uniformity. However, the positive small values of the s radioisotopes ( 348 U, 232 Th, and 40 K) concentrations, as well as those for ot ( Table 5), indicate that their distributions are not perfectly symmetric and right (positive skewed). Moreover, kurtosis is a small negative of most o reported herein as shown in Table 5. Therefore, a small flatter peak and sm distribution are assumed.
The normality of distribution for all variables was tested using the Sha The p-values of the Shapiro-Wilk test for radioisotopes (U-348, Th-232, and trations and for radiological risk parameters are all greater than 0.05 (Table  that the current data follows a normal distribution. To validate this, the And test (A-D test) was used in conjunction with the goodness of fit test (G distribution. The findings show that the data set for the radioisotopes (U-3 K-40) concentrations and other radiological variables also follow the norm where p-values greater than 0.05 for the normal test ( Table 5).

Data Statistical Analysis
The current data was statistically analyzed using both the Origin Pro 2019b and IBM SPSS statistics (version 23) software packages. The numerical and graphical outputs extracted from the statistical analysis were used for investigating the normality distribution of radioisotope concentrations and radiological parameters. Descriptive statistics for simplifying data by reducing it into a simple summary were performed. The descriptive statistics calculated include the minimum (Min), maximum (Max), mean, range, variance, standard deviation, kurtosis, and skewness ( Table 5). The histogram together with the frequency distribution curve were determined and compared with the function of normal distribution using the Shapiro-Wilk and Anderson-Darling tests (p-value > 0.05). Additionally, the potential linear relationships among variables were also statistically introduced herein via Pearson correlations analysis. For all variables (Table 5), standard deviations that are less than the means indicate a high degree of uniformity. However, the positive small values of the skewness of the radioisotopes ( 348 U, 232 Th, and 40 K) concentrations, as well as those for other parameters ( Table 5), indicate that their distributions are not perfectly symmetric and deviated to the right (positive skewed). Moreover, kurtosis is a small negative of most of the variables reported herein as shown in Table 5. Therefore, a small flatter peak and small thinner tails distribution are assumed.
The normality of distribution for all variables was tested using the Shapiro-Wilk test. The p-values of the Shapiro-Wilk test for radioisotopes (U-348, Th-232, and K-40) concentrations and for radiological risk parameters are all greater than 0.05 (Table 5), confirming that the current data follows a normal distribution. To validate this, the Anderson-Darling test (A-D test) was used in conjunction with the goodness of fit test (GFT) for normal distribution. The findings show that the data set for the radioisotopes (U-348, Th-232, and K-40) concentrations and other radiological variables also follow the normal distribution where p-values greater than 0.05 for the normal test ( Table 5).
The frequency distributions of radioisotopes concentrationsas well as those of radiological variables (Figures S1-S9 in the Supplementary Material) were shown (Figures 14-16). The majority of the histograms show some degree of bimodality. The bimodal distributions of radioisotopes in ElSibai-Abu ElTiyur granites reflect the different processes that the magma undergo during its ascending to the surface.        Pearson correlations are provided to demonstrate the potential linear relationships between the concentrations of U-238, Th-232, and K-40 and the radiological parameters (Table 6). It is evident that all considered variables are positively correlated with each other. Regarding the radioisotopes concentrations, the correlation was very strong (r > 0.8) between 238 U and 232 Th, while it was moderate (r > 0.4) between them and 40 K. Moreover, 238 U and 232 Th concentrations displayed a very strong correlation with all radiological parameters where the correlation coefficients (r) oscillated between 1 to 0.928 and 0.967 to 0.865 for 238 U and 232 Th, respectively (Table 6). On the other hand, 40 K has a weak correlation (r = 0.397) with I α , moderate correlations (0.598 ≥ r ≥ 0.4) with Ra eq , H ex , H in , YEGD, RER, IRC, and IYED Rn , and strong ones (0.63 ≥ r ≥ 0.6) with I γ , ELCR, and AGDR. It should be noted that all radiological parameters were very strongly correlated (1≥ r ≥ 0.927) with one another. 238 U and 232 Th concentrations were considerably related and responsible for the slight radiological risks that might arise, while the 40 K concentrations were less relevant. The strong positive relationships demonstrate a common formation while the moderate positive relationships reveal that their formation varies somewhat in nature.

Conclusions
The radioisotopes (U-238, Th-232, and K-40) concentrations and RER from ElSibai-Abu ElTiyur granitic samples, as well as the assessment of any potential health hazards when these rocks are used as decorative building materials, were investigated. Geochemically, uranium in the rocks of ElSibai-Abu ElTiyur is closely related to SiO2 (0.70), Rb (0.86), and Th (0.83) in rock-forming minerals. While thorium is strongly attached to Cs (0.89), Li (0.70), Pb (0.78), and Rb (0.96). Potassium, on the other hand, is highly correlated with SiO2 (0.69) and Pb (0.70). The mean values obtained for both 238 U and 232 Th concentrations in ElSibai-Abu ElTiyur granites are slightly more than GAVs of these radionuclides in regular soil, but they do not surpass their corresponding values in building materials. Meanwhile, the mean concentration of 40 K herein is high compared to their GAVs in both regular soil and building materials. However, the radiation risk indices, the absorbed yearly effective excess gamma dose rates, the excess lifetime cancer risk, the radon exhalation rate, the radon concentration, and radon yearly effective dose rate indoors are within the safe recommended levels specified in the international standards for use these granites as construction materials. According to the statistical analysis applied herein, the data of the measured radioisotope concentrations (U-348, Th-232, and K-40)-besides all the estimated radiological parameters-follow normal distributions. Furthermore, it was found that the slight radioactivity level arising from the examined granite is ascribable mainly to 238 U and 232 Th concentrations, with only a slight contribution of 40 K. The content of the radioactive elements and their hazardous parameters in the studied rocks complement the gap for the need for basic research to expand the raw material alternative for the production of building materials.