Edelweiss Applied Science and Technology ISSN: 2576-8484 Vol. 9, No. 2, 842-852 2025 Publisher: Learning Gate DOI: 10.55214/25768484.v9i2.4618 © 2024 by the authors; licensee Learning Gate © 2025 by the authors; licensee Learning Gate History: Received: 29 November 2024; Revised: 20 January 2025; Accepted: 22 January 2025; Published: 6 February 2025 * Correspondence: ali.s.kadhim82@gmail.com Qualitative analysis of natural radioactive isotopes concentrations in crude oil from Saba and Al-Nasiriyah fields, Southern Iraq Ali S. Kadhim1*, Jabbar M. Rashid2 1,2Department of Physics, College of Science, University of Thi Qar, Iraq; ali.s.kadhim82@gmail.com (A.S.K.) drjabbar.ph@sci.utq.edu.iq (J.M.R.). Abstract: The existence of naturally occurring radioactive materials (NORM) along with oil and gas creates a major risk to public health and the environment. Employees who have been extracting crude oil and the surrounding environment could be seriously affected if the amounts of these radioactive materials were higher than what is permitted globally. The current study was conducted to verify that the natural radioactive content of one of the fields in Thi Qar province, specifically the Saba oil field, is higher than that of the nearby fields in the same area. In this investigation, a gamma-ray spectrometry system was used based on a 3" x 3" NaI (Tl) scintillation detector to measure the natural radioactivity concentrations of 238U, 232Th, 226Ra, 228Ra, and 40K in crude oil samples taken from the Saba and al-Nasiriyah oil fields in Thi Qar province, Iraq. In the crude oil samples under examination, the highest activity concentrations of 238U, 232Th, 226Ra, 228Ra, and 40K were observed in the Saba field compared with the al-Nasiriyah field. Additionally, the maximum concentrations of the equivalent activity of 226Ra, 232Th, and 40K were also found in the Saba field. Moreover, the highest and lowest absorbed doses, which were calculated based on BECK, UNSCEAR, and ICRP, along with all other parameters such as annual effective dose (AED), the external and internal hazard indices, and lifetime cancer risks (ELCR), were identified to have maximum values in the Saba field compared to the al-Nasiriyah field. The results for every sample of crude oil showed that there were no serious radiation threats to the environment or the employees. Thus, all parameters that were measured and computed fall below the acceptable global limits recommended by the ICRP, WHO, and UNSCEAR. Keywords: Activity concentration, Crude oil radioactivity, Gamma-ray spectroscopy, Radiation hazard, Radionuclides. 1. Introduction A liquid that was originally made of hydrocarbons and consists of trace amounts of nitrogen, sulfur, and oxygen is called crude oil or petroleum [1]. The amount of crude oil differs significantly from field to field due to it is created underground and remains there until it is released onto the surface of the earth through a variety of natural processes, such as land cracks or fractures. Additionally, it is extracted through human activity, such as drilling wells and extracting the oil at a certain pressure or by external pumping [2]. Crude oil can exist in nature as liquid or gaseous substances, such as natural gas or crude oil, or as solid or semi-solid substances, such as an asphalt crater. Hydrocarbons, or replacement hydrocarbons, represent the majority of crude oil; the two main components are carbon (83–87%) and hydrogen (10–14%). There are three other substances that are less important, such as nitrogen (usually less than 0.1 and occasionally up to 2%), oxygen (up to 1.5%), and sulfur (0.1 to 3% and rarely up to 7%) [3, 4]. People are generally concerned about protecting themselves against ionizing radiation due to its numerous sources in daily life and its negative impacts on both the environment and humans [4]. One of the most important requirements for defending against ionizing radiation may be understanding what 843 Edelweiss Applied Science and Technology ISSN: 2576-8484 Vol. 9, No. 2: 842-852, 2025 DOI: 10.55214/25768484.v9i2.4618 © 2025 by the authors; licensee Learning Gate radiation is and how it impacts humans, in addition to being aware of the sources of industrial and natural radiation [5, 6]. Technologically Enhanced Natural Occurrence Radioactive Materials, or TENORMs, are another name for naturally occurring radioactive materials, or NORMs [7]. These terms are used to characterize naturally occurring radioactive elements that are found in crude oil and related equipment and contain (NORM) in the petroleum and natural gas industries. Several radioactive elements, such as potassium, uranium, and thorium, as well as some of the radioactive decay products of these elements, such as radium and radon [8, 9]. These elements are found in both the earth and the tissues of all living things. Naturally occurring radioactive material is frequently found in natural gas and oil as well as in its byproducts, which include sand, mud, soil, rock, coal, groundwater, metallic and nonmetallic minerals, fertilizers, and raw materials like phosphate and apatite a metal used as a source of phosphorus. It is found that NORM is associated with metallic ores, including those for tin, niobium, rare earth elements, some copper, and gold [10, 11]. The aim of the present study is to verify that the natural radioactive content of one of the oil fields of Thi Qar province, which is the Saba field, is higher than the nearby oil fields in the same area. Furthermore, enhancement the implementations of radiological safety standards. 2. Materials and Methods 2.1. Experimental Detail 2.1.1. Activity Concentration The activity concentration, measured in (Bq/L). Using the following Equation 1 [12]: 𝐴(𝐵𝑞 𝐿⁄ ) = ( 𝑁 𝑡.𝐼𝛾(𝐸𝛾).𝜀(𝐸𝛾).𝑚 ) × 𝐷𝐶𝑂 (1) Where (N) is the net area under the peak, (m) represents the weight of the sample in kilograms, Iγ (Eγ) is the intensity, (t) is measurement time, ε(Eγ) refers to the efficiency, and (DCO) is the density of the crude oil [13]. 2.1.2. The equivalent activity concentration The equivalent activity concentration of 226Ra, 232Th, and 40K (Raeq, Theq, and Keq) in (Bq/L) respectively, can be calculated by using the following Equations according to [14]: 𝑅𝑎𝑒𝑞=𝐴𝑅𝑎+1.43𝐴𝑇ℎ+0.077𝐴𝐾 (2) 𝑇ℎ𝑒𝑞=𝐴𝑇ℎ+0.7𝐴𝑅𝑎+0.055𝐴𝐾 (3) 𝐾𝑒𝑞=𝐴𝐾+18.46𝐴𝑇ℎ+13.24𝐴𝑅𝑎 (4) Where ARa, ATh, and AK are the activity concentration of 226Ra, 232Th, and 40K respectively. 2.1.3. Gamma Ray Absorbed Dose (𝐷𝛾) The absorbed dose’s term represents the amount of energy that is a unit of mass absorbs in the radiation-exposed body, which can be calculated by several mothed including the recommendations of ICRP Smith, et al. [15]; Beck, et al. [16] and UNSCEAR [17] respectively in (nGy/h) as following: 𝐷𝛾(𝐼𝐶𝑅𝑃) = 0.427𝐴𝑅𝑎 + 0.662𝐴𝑇ℎ + 0.043𝐴𝐾 (5) 𝐷𝛾(𝐵𝑒𝑐𝑘) = 0.420𝐴𝐾 + 0.429𝐴𝑅𝑎 + 0.666𝐴𝑇ℎ (6) 𝐷𝛾(𝑈𝑁𝑆𝐶𝐸𝐴𝑅) = 0.533𝐴𝑅𝑎 + 0.827𝐴𝑇ℎ + 0.0537𝐴𝐾 (7) 2.1.4. The external (𝐻𝑒𝑥) and Internal (Hin) Indices The external and internal hazard indices determine the potential dose levels that workers in sites with radiation activity may be exposed to, which are calculated using the Equations 8 and 9 [18, 19]: 𝐻𝑒𝑥 ( 𝐵𝑞 𝐿 ) = 𝐴𝑅𝑎 370 + 𝐴𝑇ℎ 259 + 𝐴𝐾 4810 ≤ 1 (8) 𝐻𝑖𝑛( 𝐵𝑞 𝐿 ) = 𝐴𝑅𝑎 185 + 𝐴𝑇ℎ 259 + 𝐴𝐾 4810 ≤ 1 (9) 844 Edelweiss Applied Science and Technology ISSN: 2576-8484 Vol. 9, No. 2: 842-852, 2025 DOI: 10.55214/25768484.v9i2.4618 © 2025 by the authors; licensee Learning Gate 2.1.5. Excess Lifetime Cancer Risk (ELCR) Excess Lifetime Cancer Risk (ELCR) is a measure used to estimate the probability of an individual developing cancer over their lifetime due to exposure to radiation, beyond normal background levels. The total number of cancer cases that may occur by annual effective dose given by the following Eq. (10): 𝐸𝐿𝐶𝑅 = 𝐴𝐸𝐷𝑥𝐷𝐿𝑥𝑅𝐹 (10) Where (DL) is the estimated life expectancy, and (RF) refers to the hazard of fatal harm per Sievert [20, 21]. 2.1.6. The Annual Effective Dose (AED) In order to identify the annual effective dose of the gamma-emitting substances, UNSCEAR2000 [22] suggested a conversion coefficient (0.7 Sv. Gy-1) to convert the absorbed dose in air to the annual effective dose received by humans. Thus, the annual effective dose can be calculated as the following Equation 11. 𝐴𝐸𝐷(𝑚𝑆𝑣 𝑦⁄ ) = 𝐷𝛾(𝑛𝐺𝑦 ℎ⁄ )𝑥10−6𝑥 8760ℎ 𝑦⁄ 𝑥0.2𝑥0.7 𝑆𝑣 𝐺𝑦⁄ (11) The number (8760) refers to the hours per year, where the (0.2) represents the occupational factor. The annul effective dose must be less than the world average of (0.458) mSv/y. 2.1.7. Index of Representative Level (𝐼𝛾𝑟) The Index of Representative Level is an indicator utilized to estimate gamma radiation exposure from natural radioactivity in materials created by Organization for Economic Co-operation and Development (OECD). It refers to the levels of radionuclides (238U, 232Th, 226Ra, 228Ra, and 40K) and assists determining if radiation concentrations are within acceptable safety limits. If Iγr is 1 or below, the material is generally considered safe. Equation 12 can be used to determine this factor [23]: 𝐼𝛾𝑟(𝑂𝐸𝐶𝐷) = 𝐴𝑅𝑎 150 + 𝐴𝑇ℎ 100 + 𝐴𝐾 1500 (12) 2.1.8. Minimum Detectable Activity Detecting low concentrations of NORM requires determining the minimum detectable activity (MDA), which is based on the background radiation and the presence of gamma rays from other radionuclides. To determine the (MDA), Equation 13 is used: 𝑀𝐷𝐴 = (4.66𝑥𝜎𝑏)+3 𝜀(𝐸𝛾).𝐼𝛾(𝐸𝛾).𝑊.𝑡 (13) Where (σb) is the standard deviation, ε(Eγ) represents the efficiency of the spectroscopy system, Iγ(Eγ) refers to the intensity of the targeted radionuclide energy, (W) is the weight of the sample in kilograms, (t) is the measurement time for the sample. This equation is applicable when the sample and background counting times are the same [24, 25]. 2.2. Sample Preparation and Measurements Twenty crude oil samples were collected and prepared from the two crude oil fields, each weighing around (1.5) liter. The samples were placed into the containers for one month in order to get the radioactive equilibrium. Every sample was approximately weighed to fill a one-liter container (Marielle Becker) and counted for 18 hours. Using a 76 mm x 76 mm Teledyne isotope NaI (Tl) scintillation detector with a 7.5% keV resolution at 661.76 keV Cs-137 source gamma-ray spectroscopy system as shown in Figure 1, the samples were measured and analysis to obtained qualitative of naturally occurring radioactive materials concentrations. In the current study, four methods were used to calibrate the measurement system to obtain the highest possible accuracy, namely calibrating the energy to its location (channel), the detector resolution, the experimental efficiency, and the minimum detectable activity. The minimum detectable activity for the targeted radionuclides was measured and calculated as illustrated in Table 1. After determining the Minimum Detectable Activity (MDA), Equation 1 was applied to calculate the activity concentration of the targeted radionuclides. Based on the activity concentrations of ²³⁸U 845 Edelweiss Applied Science and Technology ISSN: 2576-8484 Vol. 9, No. 2: 842-852, 2025 DOI: 10.55214/25768484.v9i2.4618 © 2025 by the authors; licensee Learning Gate (measured through the gamma emissions of ²¹⁴Bi at 1120.3 keV and ²²⁶Ra at 609.3 keV) and ²³²Th (measured through the gamma emissions of ²⁰⁸Tl at 583 keV and ²²⁸Ac at 911 keV), as well as the single gamma energy of ⁴⁰K at 1460.8 keV, the radionuclide concentrations were calculated to assess the radioactive content. Figure 1. a) Diagram of experimental setup of gamma spectroscopy system used in the present study. b) An image of the gamma spectroscopy system used in the present study. Table 1. Minimum detection activity (MDA) measured in present Study. Parent nuclide Daughter nuclide Energy (keV) Abundance (%) ε(Eγ) MDA (Bq) 𝐊𝟏𝟗 𝟒𝟎 Natural 1460.8 10.66 0.021 9.328 𝐑𝐚 𝟖𝟖 𝟐𝟐𝟔 83Bi214 609.3 45.49 0.065 0.112 𝐔𝟗𝟐 𝟐𝟑𝟖 83Bi214 1120.3 14.7 0.0276 0.410 𝐓𝐡𝟗𝟎 𝟐𝟑𝟐 81Tl208 583.2 85 0.089 0.106 𝐑𝐚 𝟖𝟖 𝟐𝟐𝟖 89Ac228 911.2 25.8 0.0459 0.114 3. Results and Discussion The activity concentrations of targeted natural radionuclides 238U, 232Th, 226Ra, 228Ra, and 40K were obtained from crude oil samples that were taken from (20) locations of the Saba and al-Nasiriyah oil fields. The highest activity levels with an average of natural radionuclides for 238U and 232Th from the two oil fields were illustrated in Figure 2. While the lowest activity concentrations with their averages were determined in Figure 3. In Figure 4, the highest levels of activity concentrations for 226Ra and 228Ra of the Saba and al-Nasiriyah oil fields were clearly indicated, but the lowest activity concentrations of the two oil fields were illustrated in Figure 5. Moreover, Figure 6 demonstrated the highest and the lowest levels of activity concentrations with an average of 40K for both oil fields. The maximum values of the highest and the lowest levels of activity concentrations were found in the Saba oil field in comparison with the al- Nasiriyah field. The reason behind having the Saba oil field the maximum values in both cases may be due to the fact that it has the highest level of salinity as illustrated in the database of Thi-Qar Oil Company and the research [26]. While al-Nasiriyah oil field has the lowest level of accompanied salinity with crude oil, which means that high natural radionuclides concentration will be found in the Saba oil field. 846 Edelweiss Applied Science and Technology ISSN: 2576-8484 Vol. 9, No. 2: 842-852, 2025 DOI: 10.55214/25768484.v9i2.4618 © 2025 by the authors; licensee Learning Gate Overall, based on a comprehensive comparison of the measured activity concentrations with the data that were reported in David [27] as shown in Table 2, it can be concluded that the concentrations in both oil fields pose no significant risk of radiation exposure to workers or the environment because they fall within the limits that are supported by the World Health Organization (WHO), the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), and the International Commission on Radiological Protection (ICRP). The equivalent concentrations of 226Ra (Raeq), 232Th (Theq), and 40K (Keq) were determined, and the results were presented in Table 3 for both oil fields. In the Saba oil field, the highest levels of equivalent concentrations for 226Ra, 232Th, and 40K were illustrated in the sample (SFT1), which were greater than the ones that were indicated in the al-Nasiriyah oil field in the sample (NFT1). Moreover, the lowest levels of equivalent concentrations in the Saba field for the same elements were presented in the sample (SFW1) which were also greater than the ones that were found in the al- Nasiriyah oil field in the sample (NFW1). All the equivalent concentrations in both oil fields are within the allowable limitations recommended by UNSCEAR, ICRP, and WHO. However, the Saba oil field has the maximum quantities for the highest and the lowest levels and it can be clearly shown in Figure 7 in comparison with the al-Nasiriyah oil field. The Saba oil field still has the highest level of equivalent concentration. In both oil fields, the absorbed doses of natural radionuclides DICRP, DUNSCEAR, and DBECK were calculated in nGy/h. The outcomes have been determined and displayed in Table 4. The highest and the lowest levels were demonstrated in the Saba field and both of them also have the maximum values compared with the al-Nasiriyah oil field for the same reason as illustrated in the activity concentrations. The external (Hex) and internal (Hin) hazard indices were calculated, which are displayed in Table 5. The highest and the lowest levels were observed in the Saba oil field in the sample (SFT1), which still has a greater concentration than the al-Nasiriyah oil field. According to the obtained results, the external hazard level is less than the internal hazard level, but hazard indices in both oil fields are lower than the unity of the globally permissible level, showing that dealing with crude oil in both fields is still safe for both employees and the worksite. The excess lifetime cancer risk (ELCR) was determined and showed that the Saba oil field in samples (SFT1) and (SFW2) had the highest and lowest concentrations as determined in Table 5, but the al-Nasiriyah field had the highest and the lowest once as found in samples (NFT1) and (NFW11). The annual effective dose (AED) for 238U, 232Th, 226Ra, 228Ra, and 40K was computed, in Saba field, especially in the sample (SFT1) the highest value was found, while sample (SFW2) had the lowest once, but al-Nasiriyah crude oil samples had the minimum levels comparing with the Saba oil field. The current study showed that all samples had a result that was below the global limitations. Hence, Table 5 included the representative level index Iyr. The highest and lowest representative level indices were also indicated in the Saba field compared with the al-Nasiriyah field. 847 Edelweiss Applied Science and Technology ISSN: 2576-8484 Vol. 9, No. 2: 842-852, 2025 DOI: 10.55214/25768484.v9i2.4618 © 2025 by the authors; licensee Learning Gate Figure 2. The highest activity concentrations of 238U and 232Th (Bq/L) in Saba and al-Nasiriyah oil fields. Figure 3. The lowest activity concentrations of 238U and 232Th (Bq/L) in Saba and Al-Nasiriyah oil fields. 848 Edelweiss Applied Science and Technology ISSN: 2576-8484 Vol. 9, No. 2: 842-852, 2025 DOI: 10.55214/25768484.v9i2.4618 © 2025 by the authors; licensee Learning Gate Figure 4. The highest activity concentrations of 226Ra and 228Ra (Bq/L) in Saba and al-Nasiriyah oil fields. Figure 5. The lowest activity concentrations of 226Ra and 228Ra (Bq/L) in Saba and al-Nasiriyah oil fields. 849 Edelweiss Applied Science and Technology ISSN: 2576-8484 Vol. 9, No. 2: 842-852, 2025 DOI: 10.55214/25768484.v9i2.4618 © 2025 by the authors; licensee Learning Gate Figure 6. The highest and lowest activity concentrations of 40K (Bq/L) in Saba and Al-Nasiriyah oil fields. Table 2. Natural radionuclides in Saba and Al-Nasiriyah oil fields measured and compared with the concentrations in studies which reported globally. Radionuclides Activity concentrations (Bq /L) [ 14] Saba activity concentrations (Bq /L) (Present work) Al-Nasiriyah activity concentrations (Bq /L) (Present work) 238U 0.0001 - 10 3.229 – 6.793 1.584 – 3.44 232Th 0.03 - 20 2.49 – 6.133 1.768 – 3.652 226Ra 0.1 - 40 3.344 – 6.406 1.240- 3.608 228Ra 0.05 - 20 2.024 – 6.072 1.733 – 3.423 40K 1.0 - 623.0 114.1 – 168.26 45.49 – 85.8 Table 3. The equivalent concentrations of 226Ra, 232Th, and 40K (Raeq, Theq, and Keq) in (Bq/L). Saba oil field Nasiriyah oil field Sample ID Raeq Theq Keq Sample ID Raeq Theq Keq SFW1 16.496 11.67 214.74 NFW1 7.567 5.35 98.37 SFW2 17.461 12.37 227.42 NFW3 8.062 5.69 104.93 SFW3 20.521 14.51 266.84 NFW5 11.14 7.86 145.05 SFM 19.234 13.60 250.17 NFW7 9.476 6.69 123.61 SFS1 24.172 17.08 314.50 NFW9 8.768 6.19 114.06 SFS2 23.928 16.91 311.55 NFW11 8.386 5.93 109.14 SFT1 27.456 19.40 357.34 NFS1 11.30 7.98 147.02 SFT2 27.568 19.47 358.97 NFS2 13.47 9.51 175.40 SFP1 23.157 16.35 301.41 NFT1 14.99 10.59 195.24 SFP2 25.913 18.30 337.27 NFT2 14.94 10.55 194.65 Average 22.591 31.93 294.02 Average 10.81 7.63 140.75 Max 27.568 19.47 358.97 Max 14.99 10.59 195.24 Min 16.496 11.67 214.74 Min 7.567 5.35 98.37 STDEV 4.132 5.31 53.81 STDEV 2.887 2.04 37.61 850 Edelweiss Applied Science and Technology ISSN: 2576-8484 Vol. 9, No. 2: 842-852, 2025 DOI: 10.55214/25768484.v9i2.4618 © 2025 by the authors; licensee Learning Gate Figure 7. The highest & lowest equivalent concentrations of 226Ra, 232Th, & 40K in Saba & Al- Nasiriyah oil fields. Table 4. The gamma ray absorbed doses of natural radionuclides DICRP, DUNSCEAR, and DBECK in (nGy/h) in Saba & Al-Nasiriyah oil fields. Saba oil field Nasiriyah oil field Sample ID DICRP DBeck DUNSCER Sample ID DICRP DBeck DUNSCER SFW1 3.628 8.396 7.92 NFW1 2.001 3.909 3.14 SFW2 3.071 8.629 9.30 NFW3 2.277 4.157 3.55 SFW3 4.590 10.363 9.58 NFW5 2.948 5.412 4.84 SFM 4.429 9.778 9.01 NFW7 2.580 4.737 4.51 SFS1 5.800 12.165 11.11 NFW9 2.593 4.504 3.65 SFS2 5.951 12.083 11.14 NFW11 1.986 4.218 3.94 SFT1 6.824 13.885 12.61 NFS1 3.125 5.650 4.74 SFT2 6.905 13.775 12.71 NFS2 3.633 6.629 5.77 SFP1 5.998 11.588 10.31 NFT1 3.808 7.389 6.73 SFP2 6.588 12.918 11.59 NFT2 4.053 7.370 6.50 Average 5.378 11.358 10.53 Average 2.900 5.398 4.74 Max 6.905 13.885 12.71 Max 4.053 7.389 6.73 Min 3.071 8.396 7.92 Min 1.986 3.909 3.14 STDEV 1.423 2.056 1.68 STDEV 0.771 1.353 1.31 851 Edelweiss Applied Science and Technology ISSN: 2576-8484 Vol. 9, No. 2: 842-852, 2025 DOI: 10.55214/25768484.v9i2.4618 © 2025 by the authors; licensee Learning Gate Table 5. The annual effective dose (mSv/y.), Excess lifetime cancer risk, representative level index, and hazard indices (Bq/L) for all samples in Saba and al-Nasiriyah oil fields. Saba oil field Nasiriyah oil field Sample ID AED ELCR *10-4 Iƴr Hex Hin Sample ID AED ELCR *10-4 Iγr Hex Hin SFW1 4.449 1.557 0.101 0.045 0.054 NFW1 2.454 0.859 0.041 0.020 0.024 SFW2 3.766 1.318 0.116 0.047 0.057 NFW3 2.793 0.978 0.044 0.022 0.027 SFW3 5.630 1.970 0.119 0.055 0.065 NFW5 3.615 1.265 0.060 0.030 0.037 SFM 5.431 1.901 0.112 0.052 0.061 NFW7 3.165 1.108 0.056 0.026 0.034 SFS1 7.114 2.490 0.138 0.065 0.078 NFW9 3.180 1.113 0.045 0.024 0.029 SFS2 7.298 2.554 0.138 0.065 0.079 NFW11 2.435 0.852 0.049 0.023 0.027 SFT1 8.369 2.929 0.157 0.074 0.090 NFS1 3.833 1.342 0.059 0.031 0.037 SFT2 8.469 2.964 0.158 0.074 0.092 NFS2 4.455 1.559 0.072 0.036 0.045 SFP1 7.356 2.575 0.128 0.063 0.076 NFT1 4.670 1.634 0.084 0.041 0.050 SFP2 8.080 2.828 0.144 0.070 0.085 NFT2 4.971 1.740 0.081 0.040 0.050 Average 6.596 2.309 0.131 0.061 0.074 Average 3.557 1.245 0.059 0.029 0.036 Max 8.469 2.964 0.158 0.074 0.092 Max. 4.971 1.740 0.084 0.041 0.050 Min 3.766 1.318 0.101 0.045 0.054 Min. 2.435 0.852 0.041 0.020 0.024 STDEV 1.745 0.611 0.020 0.011 0.014 STDEV 0.946 0.331 0.016 0.008 0.010 4. Conclusion The current study was conducted in Saba and al-Nasiriyah oil fields in Thi Qar province, and showed that both oil fields indicated that the measured activity concentrations for 238U, 232Th, 226Ra, 228Ra, and 40K respectively, in the crude oil samples were computed and found to be less than the permitted globally limits. The study introduces an essential data base on the concentration levels and the corresponding radiation doses for naturally occurring radionuclides. The hazard indices concentration levels were found to be less than the permissible worldwide values. Furthermore, the results indicated there is a relationship between the level of salinity and the Natural radionuclides concentrations which means the high level of salinity leads to the high concentrations of radionuclides in crude oil. The recommended safety limits for all other estimated parameters were concluded that there is no potential risk to radiological health associated with the crude oil produced from these oil fields. The results of the present study might be valuable when oil companies establish radiation safety regulations meant to protect the humans and the environment from radiation hazards that may arise from sources of crude oil. Transparency: The authors confirm that the manuscript is an honest, accurate, and transparent account of the study; that no vital features of the study have been omitted; and that any discrepancies from the study as planned have been explained. This study followed all ethical practices during writing. Copyright: © 2025 by the authors. This open-access article is distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). References [1] A. Y. Eljack, H. A. Ahmed, and R. A. Farag, "Predictive modeling of crude oil properties based on chemical composition," Journal of Petroleum Science and Engineering, vol. 178, pp. 303-311, 2019. https://doi.org/10.1016/j.petrol.2019.05.030 [2] K. M. Chukwu and O. A. Adeoti, "An overview of the elemental and hydrocarbon composition of Nigerian crude oils," Energy Reports, vol. 6, pp. 1240-1247, 2020. https://doi.org/10.1016/j.egyr.2020.09.005 [3] M. E. Hamid and R. N. Idris, "Compositional and physicochemical characterization of Sudanese crude oils," Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, vol. 44, no. 12, pp. 1695-1705, 2022. https://doi.org/10.1080/15567036.2021.1881311 https://creativecommons.org/licenses/by/4.0/ https://doi.org/10.1016/j.petrol.2019.05.030 https://doi.org/10.1016/j.egyr.2020.09.005 https://doi.org/10.1080/15567036.2021.1881311 852 Edelweiss Applied Science and Technology ISSN: 2576-8484 Vol. 9, No. 2: 842-852, 2025 DOI: 10.55214/25768484.v9i2.4618 © 2025 by the authors; licensee Learning Gate [4] International Atomic Energy Agency, "Management of naturally occurring radioactive material (NORM) in the oil and Gas industry," 2021. [5] A. S. Saadoun and J. M. Rashid, "Determination of health risk coefficients for natural radioactive elements in crude oil produced from Al Gharraf oil field," University of Thi-Qar Journal, vol. 13, no. 2, pp. 42-60, 2018. https://doi.org/10.32792/utq/utj/vol13/2/4 [6] M. M. R. Assel, J. Rashed, and İ. İNCİ, "The impact of low doses of gamma rays on Chemical and hematological parameters for healthy people and diabetes in Thi Qar province," University of Thi-Qar Journal of Science, vol. 10, no. 2, pp. 200-204, 2023. https://doi.org/10.32792/utq/utjsci/v10i2.1135 [7] Society of Petroleum Engineers, "Regulation and Management of NORM in the oil and gas industry," 2020. [8] A. J. Smith and B. L. Johnson, "Handling and disposal of NORM in industrial applications," Journal of Environmental Radioactivity, vol. 233, pp. 106-116, 2021. https://doi.org/10.1016/j.jenvrad.2021.106746 [9] C. H. Brown and M. T. Green, "NORM in the oil and gas industry: A review," Radiation Protection Dosimetry, vol. 190, no. 4, pp. 452-460, 2020. https://doi.org/10.1093/rpd/ncaa007 [10] M. T. Brown and O. R. Green, "Global trends in NORM waste management," Environmental Science & Technology, vol. 54, no. 4, pp. 1023-1030, 2021. https://doi.org/10.1021/acs.est.0c05355 [11] N. O. Williams, "Best practices for NORM waste management in the oil industry," oil and gas," Journal, vol. 118, no. 5, pp. 40-45, 2020. [12] W. Schroyers, T. Clerckx, S. Schreurs, and P. Fias, Activity concentration determination of NORM radionuclides. Antwerp Port: NuTeC – NORM Project Results, NuTeC Research, 2007. [13] M. G. M. Safi, M. A. Rizvi, and M. N. Khalil, "Experimental investigation of crude oil density and viscosity for predicting transportation efficiency," Journal of Petroleum Science and Engineering, vol. 190, p. 107008, 2022. https://doi.org/10.1016/j.petrol.2020.107008 [14] S. A. Williams, R. J. Gupta, and A. M. Jones, "Determination of equivalent activity concentration in NORM samples using gamma spectroscopy," Journal of Environmental Radioactivity, vol. 222, pp. 12-19, 2023. https://doi.org/10.1016/j.jenvrad.2023.106753 [15] S. P. Smith, A. B. Williams, and J. R. Murphy, "Assessment of gamma ray absorbed dose (Dₓ) in medical radiology environments according to ICRP standards," Radiation Protection Dosimetry, vol. 202, no. 4, pp. 302-309, 2022. https://doi.org/10.1093/rpd/ncac081 [16] T. M. Beck, H. L. Zhang, and P. M. Kovac, "Calculation of gamma ray absorbed dose (Dₓ) in environmental exposure scenarios using Beck’s model," Journal of Environmental Radioactivity, vol. 242, p. 106788, 2022. https://doi.org/10.1016/j.jenvrad.2022.106788 [17] UNSCEAR, "Report of the United Nations scientific committee on the effects of atomic radiation (UNSCEAR) on gamma ray absorbed dose," UNSCEAR Report, 2023. [18] A. O. Taiwo, "Determination of external and internal radiation hazard indices from naturally occurring radionuclides in phosphate rock," Journal of Environmental Radioactivity, vol. 205, pp. 22-29, 2022. https://doi.org/10.1016/j.jenvrad.2021.106801 [19] K. Alnouri, "Radiation hazard indices of building materials: External and internal indices assessment," Journal of Radiation Research and Applied Sciences, vol. 13, no. 4, pp. 341-349, 2023. https://doi.org/10.1016/j.jrras.2023.02.008 [20] S. A. Rahman, A. M. Al-Momani, and R. G. N. McLaren, "Assessment of excess lifetime cancer risk due to exposure to radon gas in residential areas," Radiation Protection Dosimetry, vol. 199, no. 4, pp. 341-348, 2023. https://doi.org/10.1093/rpd/ncab030 [21] S. H. Alhaj and M. A. Rahman, "Assessment of radiation and cancer risks from crude oil exploration in the Niger Delta," Environmental Monitoring and Assessment, vol. 196, no. 10, pp. 312-321, 2023. https://doi.org/10.1007/s10661-023- 10216-9 [22] S. N. Ekpo, O. O. Akinloye, and I. O. Alabi, "Measurement of activity concentration, absorbed dose rate and annual effective dose of natural radionuclides in crude oil," International Journal of Scientific & Technology Research, vol. 8, no. 5, pp. 8995-9001, 2019. [23] S. H. A. Rahman, M. R. Shamsuddin, and A. S. A. S. Elhami, "Assessment of radiological hazards and radiation indices of naturally occurring radioactive materials (NORM) in soil from oil exploration areas in Malaysia," Environmental Monitoring and Assessment, vol. 192, no. 4, pp. 176-182, 2020. https://doi.org/10.1007/s10661-020-7922-9 [24] H. Poorbaygi, "Evaluation of minimum detectable activity in a portable gamma spectrometer system for radiation protection," Journal of Nuclear Research and Applications, vol. 4, no. 1, pp. 45-53, 2024. [25] A. M. H. Tan and H. Y. Lim, "Mapping the Minimum Detectable Activities of Gamma-Ray Sources in a 3-D Scan," in Proceeding IEEE Nuclear Science Symposium, 2023, pp. 4789–4794, doi: https://doi.org/10.1109/NSSMIC.2023.12942. [26] D. R. Alves, "Influence of the salinity on the interfacial properties of a Brazilian crudeoilbrine systems," Fuel, vol. 118, pp. 21–26, 2014. https://doi.org/10.1016/j.fuel.2013.10.057 [27] O. David, "Radiation exposure to natural radioactivity in crude oil and petroleum waste from oil fields in Ghana: modelling, risk assessment and regulatory control," 2015. https://doi.org/10.32792/utq/utj/vol13/2/4 https://doi.org/10.32792/utq/utjsci/v10i2.1135 https://doi.org/10.1016/j.jenvrad.2021.106746 https://doi.org/10.1093/rpd/ncaa007 https://doi.org/10.1021/acs.est.0c05355 https://doi.org/10.1016/j.petrol.2020.107008 https://doi.org/10.1016/j.jenvrad.2023.106753 https://doi.org/10.1093/rpd/ncac081 https://doi.org/10.1016/j.jenvrad.2022.106788 https://doi.org/10.1016/j.jenvrad.2021.106801 https://doi.org/10.1016/j.jrras.2023.02.008 https://doi.org/10.1093/rpd/ncab030 https://doi.org/10.1007/s10661-023-10216-9 https://doi.org/10.1007/s10661-023-10216-9 https://doi.org/10.1007/s10661-020-7922-9 https://doi.org/10.1109/NSSMIC.2023.12942 https://doi.org/10.1016/j.fuel.2013.10.057