Radioactive Assessment and Th-, Nb-Ta-, Zr-, REE-Bearing Minerals in Alkaline Syenite: Environmental Implications for Radiological Safety

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Review Report on MS#: “geosciences-3515877-peer-review-v2”
Title: Radioactive Assessment and Th-, Nb-Ta-, Zr-, REE-Bearing Minerals in Alkaline Syenite: Environmental Implications for Radiological Safety
Authors: Abdel Gawad et al. 2025.

In general, this is a well-written and well-organized paper that significantly contributes to the knowledge of radioactivity and mineralization in alkaline syenite. It effectively describes Th-, Nb-Ta-, Zr-, and REE-bearing minerals and assesses the environmental risks associated with alkaline syenite from Nikeiba, Egypt.

The introduction needs revision to ensure a clearer focus on the topic. It should include more details on previous studies in the area and, if possible, similar studies on other syenite bodies in the Eastern Desert. Additionally, the conclusion should be reorganized into bullet points for improved readability."

In addition to the comments and corrections noted in the attached PDF, key points for revision are summarized as follows:

1. Title: The location of the alkaline syenite should be specified as "at Nikeiba, South Eastern Desert, Egypt."
2. Line 18-19: Please delete these lines.
3. Line 22: Delete "than others."
4. Line 20: Correct "TREE₂O₃" to subscript format (TREE₂O₃); apply this correction throughout the manuscript and tables.
5. Lines 42-51 (Introduction): Please delete these lines.
6. Figure 2c and 2d: Add "Qz Sy" to the photos.
7. Figure 3f: Verify if the labeled mineral is indeed Plagioclase (Plg).
8. Line 163: Add the appropriate mineral abbreviation.
9. Lines 244-248: These lines seem unnecessary and can be removed.
10. Figure 4: Adjust the figure layout and include subfigures 4d, 4e, and 4f in the photos.
11. Lines 401-402: Revise to:
    "It is followed by Nd₂O₃, La₂O₃, Pr₂O₃, and Sm₂O₃, with average contents of 13.74, 12.08, 3.07, and 2.83 wt%, respectively."
12. Lines 404-405: Correct to:
    "Radioactive elements, including thorium and uranium, are present, with ThO₂ and UO₂ reaching 2.72 wt% and 0.52 wt%, respectively."
13. Conclusion: Organize the conclusion into bullet points for better readability.

Overall, this paper provides valuable insights into mineralization and radiological safety. Once the suggested revisions are addressed, it will be suitable for publication.

Comments for author File: Comments.pdf

Author Response

Responses to Reviewer’s Comments
We sincerely appreciate the reviewer's professional feedback on our manuscript, as it provides valuable insights that greatly contribute to enhancing its quality. Carefully considering each comment, we have diligently revised and improved the manuscript, aiming to address all pertinent points raised. 
We have responded to the comments point by point with red font in the revised manuscript. 
Reviewer 1:
Review Report on MS#: “geosciences-3515877-peer-review-v2” 
Title: Radioactive Assessment and Th-, Nb-Ta-, Zr-, REE-Bearing Minerals in Alkaline Syenite: Environmental Implications for Radiological Safety 
Authors: Abdel Gawad et al. 2025.
In general, this is a well-written and well-organized paper that significantly contributes to the knowledge of radioactivity and mineralization in alkaline syenite. It effectively describes Th-, Nb-Ta-, Zr-, and REE-bearing minerals and assesses the environmental risks associated with alkaline syenite from Nikeiba, Egypt.
The introduction needs revision to ensure a clearer focus on the topic. It should include more details on previous studies in the area and, if possible, similar studies on other syenite bodies in the Eastern Desert. Additionally, the conclusion should be reorganized into bullet points for improved readability."
In addition to the comments and corrections noted in the attached PDF, key points for revision are summarized as follows:
Comment 1: Title: The location of the alkaline syenite should be specified as "at Nikeiba, South Eastern Desert, Egypt."
Response: Thank you for your recommendation. The part "at Nikeiba, South Eastern Desert, Egypt." stated in the whole text of the manuscript, especially the geological setting section. Therefore, the authors hope the reviewer confirms the present title. 

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Comment 2: Line 18-19: Please delete these lines.
Response: we have deleted the lines
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Comment 3: Line 22: Delete "than others."
Response: have been deleted
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Comment 4: Line 20: Correct "TREE₂O₃" to subscript format (TREE₂O₃); apply this correction throughout the manuscript and tables.
Response: has been corrected throughout the manuscript and tables.
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Comment 5: Lines 42-51 (Introduction): Please delete these lines.
Response: have been deleted
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Comment 6: Figure 2c and 2d: Add "Qz Sy" to the photos.
Response: Qz refers to quartz as a mineral not rock
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Comment 7: Figure 3f: Verify if the labeled mineral is indeed Plagioclase (Plg).
Response: we have corrected Ab into Plg
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Comment 8: Line 163: Add the appropriate mineral abbreviation.
Response: mineral abbreviations have been added. 
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Comment 9: Lines 244-248: These lines seem unnecessary and can be removed.
Response: Essential equations that have been utilized for the calculation of different Environmental parameters as well as Radiological Hazards. Therefore, it’s not logical to remove the equations of calculations from the manuscript.  
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Comment 10: Figure 4: Adjust the figure layout and include subfigures 4d, 4e, and 4f in the photos.
Response: we have done.
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Comment 11: Lines 401-402: Revise to: "It is followed by Nd₂O₃, La₂O₃, Pr₂O₃, and Sm₂O₃, with average contents of 13.74, 12.08, 3.07, and 2.83 wt%, respectively."
Response: we have added.
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Comment 12: Lines 404-405: Correct to:"Radioactive elements, including thorium and uranium, are present, with ThO₂ and UO₂ reaching 2.72 wt% and 0.52 wt%, respectively."
Response: we have added.
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Comment 13: Conclusion: Organize the conclusion into bullet points for better readability.
Response: the conclusion section has been modified.
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We have corrected all the suggested comments in the annotated pdf file as your recommendation.
We have deleted all average chemical formulae
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Overall, this paper provides valuable insights into mineralization and radiological safety. Once the suggested revisions are addressed, it will be suitable for publication.
Many thanks for your effort and suggestion  

Reviewer 2 Report

Comments and Suggestions for Authors

This is an interesting paper in which writers focused on identifying Th-, Nb-Ta-, Zr-, REE-bearing minerals and multivariate statistical approach in alkaline syenite to evaluate their radiological risks, at Nikeiba, Egypt. Thorite, microlite, monazite, zircon, columbite and fergusonite bearing uranium and thorium in their microchemical analyses by utilizing electron probe microanalysis. All these minerals give rise to higher radioactive zones in the investigated alkaline syenite.Radiological assessments revealed a radium equivalent activity of an air-absorbed dose rate (166 nGy/h) and annual effective doses (0.81 mSv/y indoors, 0.20 mSv/y outdoors) exceeding safe thresholds.the excess lifetime cancer risk (ELCR) was calculated at 0.00071, surpassing the acceptable limit of 0.00029, making these rocks unsafe for construction use. Statistical analyses further underscored the relationships between radionuclide concentrations and associated risks, highlighting the necessity for continuous monitoring and mitigation. The research results will benefit peoples living in the study area.This contribution provides new insights not only on the environment geologists, but also on the cancer prevention and treatment workers.

 

Suggestions

1. Analytical units should be lined out in Table 2,3,4,5,6,7.

 

 

 

 

Author Response

Responses to Reviewer’s Comments
Reviewer 2:
Comments and Suggestions for Authors
This is an interesting paper in which writers focused on identifying Th-, Nb-Ta-, Zr-, REE-bearing minerals and multivariate statistical approach in alkaline syenite to evaluate their radiological risks, at Nikeiba, Egypt. Thorite, microlite, monazite, zircon, columbite and fergusonite bearing uranium and thorium in their microchemical analyses by utilizing electron probe microanalysis. All these minerals give rise to higher radioactive zones in the investigated alkaline syenite. Radiological assessments revealed a radium equivalent activity of an air-absorbed dose rate (166 nGy/h) and annual effective doses (0.81 mSv/y indoors, 0.20 mSv/y outdoors) exceeding safe thresholds. the excess lifetime cancer risk (ELCR) was calculated at 0.00071, surpassing the acceptable limit of 0.00029, making these rocks unsafe for construction use. Statistical analyses further underscored the relationships between radionuclide concentrations and associated risks, highlighting the necessity for continuous monitoring and mitigation. The research results will benefit peoples living in the study area. This contribution provides new insights not only on the environment geologists, but also on the cancer prevention and treatment workers.
 
Suggestions
Comment 1: Analytical units should be lined out in Table 2,3,4,5,6,7.

Response: All oxides in Wt% have been add as mentioned in Supplementary materials.
 
We sincerely appreciate your time and your efforts
Many thanks

 

Reviewer 3 Report

Comments and Suggestions for Authors

This manuscript presents systematical study of the mineralogy, geochemistry, and radiological hazards of alkaline syenite from Nikelba, Egypt. The work addresses a scientific question in understanding the environmental risks posed by rare metal-bearing minerals in igneous rocks, particularly in the context of construction material safety. The manuscript provides new EPMA and gama spectrometry data on Th-, Nb-Ta-, and REE-minerals in Egyptian alkaline syenite, and a significant addition to the fields of geochemistry and environmental radiology. However, there are still several aspects need improvement before formally published in Geosciences.

1. Introduction: The link between rare metal mineralization and radiological hazards could be further improved.

< !-- [if !supportLists]-->2.      < !--[endif]-->Geologic Setting: Detailed but overly descriptive, could be shorter and concise.

< !-- [if !supportLists]-->3.      < !--[endif]-->Methods: Comprehensive but a little repetitive. EPMA is well-documented, but the subsection 4.2. could be condensed. Please check if the analyze spot is really less than 1μm.

4.      < !--[endif]-->Results: Some tables lack sample numbers. Tables 1–7 are informative, but too many tables in the text and can be listed in the supplementary materials.

< !-- [if !supportLists]-->5.      < !--[endif]-->Discussion: Focused on radiological parameters but insufficiently connects mineralogical data to environmental risks. Activity concentrations are compared to global averages, but the geological controls (e.g., magmatic vs. hydrothermal processes) on U/Th/K distribution are overlooked. Pearson correlations (Table 10) and PCA (Fig. 6b) are underutilized. For instance, the strong link between ²³⁸U and Raeq-Dair can be considered to be tied to mineral hosts (such as thorite or microlite).

Comments on the Quality of English Language

It is better to do thorough proofreading and to keep consistent formatting.

The language is generally clear but there are some spelling mistakes (e.g., “reched up” → “reached up”; “predominance” → “predominance”), repetitive phrasing (e.g., “marked” is overused) and inconsistent terminology (e.g., “ferrocolumbite” vs. “ferro-columbite”, “Bq kg⁻¹” vs. “Bq/kg”).

 

Author Response

Responses to Reviewer’s Comments
We sincerely appreciate the reviewer's professional feedback on our manuscript, as it provides valuable insights that greatly contribute to enhancing its quality. Carefully considering each comment, we have diligently revised and improved the manuscript, aiming to address all pertinent points raised. 
We have responded to the comments point by point with red font in the revised manuscript. 
Reviewer 3:
Author's Reply to the Review Report 
Comments and Suggestions for Authors
This manuscript presents systematical study of the mineralogy, geochemistry, and radiological hazards of alkaline syenite from Nikelba, Egypt. The work addresses a scientific question in understanding the environmental risks posed by rare metal-bearing minerals in igneous rocks, particularly in the context of construction material safety. The manuscript provides new EPMA and gama spectrometry data on Th-, Nb-Ta-, and REE-minerals in Egyptian alkaline syenite, and a significant addition to the fields of geochemistry and environmental radiology. However, there are still several aspects need improvement before formally published in Geosciences.
Comment 1. Introduction: The link between rare metal mineralization and radiological hazards could be further improved.
Response: 
–    The rare metals mineralization is widely distributed in granites especially in the Arabian-Nubian Shield (ANS) that have a great attention from economic geologists. These granites are good resources for Zr, Nb, Ta, Sn, Au, B, Be, Li, W, Mo, U, Th and REEs mineralization and possessing higher radiological hazards in many regions such as Ras Abda, Muweilha, Um Naggate, Nuweibi, Abu Dabbab, Um Safi, Um Ara-Um Shilman, El Sela, [16–21, Azer ; Surour; Sami; Abdelfadil].
–    The main objective of the present study provide the linkage between the micro-chemical analyses by utilizing electron probe microanalysis (EPMA) of the investigated rare metals mineralization and radiological hazards in the alkaline syenite at Nikeiba.  
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Comment 2.      Geologic Setting: Detailed but overly descriptive, could be shorter and concise.
Response: Geologic setting has been modified to be more concise.
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Comment 3.      Methods: Comprehensive but a little repetitive. EPMA is well-documented, but the subsection 4.2. could be condensed. Please check if the analyze spot is really less than 1μm.
Response: Thank you for your recommendation. The section 4.2 is condensed and rewritten. 
–    The analyzed spot beam diameter is 1–2 μm. 
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Comment 4.      Results: Some tables lack sample numbers. Tables 1–7 are informative, but too many tables in the text and can be listed in the supplementary materials.
Response: We agree with your recommendation. The tables in the manuscript are 7 tables and the others moved to Supplementary materials. 

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Comment 5.      Discussion: Focused on radiological parameters but insufficiently connects mineralogical data to environmental risks. Activity concentrations are compared to global averages, but the geological controls (e.g., magmatic vs. hydrothermal processes) on U/Th/K distribution are overlooked. Pearson correlations (Table 10) and PCA (Fig. 6b) are underutilized. For instance, the strong link between ²³⁸U and Raeq-Dair can be considered to be tied to mineral hosts (such as thorite or microlite).
Response: These statistical patterns likely reflect the mineralogical and geochemical processes responsible for the distribution of radionuclides in the alkaline syenite. The higher concentration of potassium compared to uranium and thorium is expected, given that potassium is a major component in many rock-forming minerals (orthoclase and microcline, along with potassium-rich micas like biotite and muscovite, whereas uranium and thorium tend to be present in trace amounts. The relatively moderate variability in 238U and 232Th suggests that these radionuclides are uniformly distributed in the syenite rock matrix, with some localized enrichment in uranium-bearing minerals. In alkaline syenite, uranium is mainly found in microlite, while thorium occurs in thorite and monazite. 
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Comments on the Quality of English Language
It is better to do thorough proofreading and to keep consistent formatting.
The language is generally clear but there are some spelling mistakes (e.g., “reched up” → “reached up”; “predominance” → “predominance”), repetitive phrasing (e.g., “marked” is overused) and inconsistent terminology (e.g., “ferrocolumbite” vs. “ferro-columbite”, “Bq kg⁻¹” vs. “Bq/kg”).
Response: All have been corrected.
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Reviewer 4 Report

Comments and Suggestions for Authors

Abdel Gawad et al. present results identifying the radioactive minerals present in alkaline syenite deposits in Egypt and their implications for radiological hazards. Overall, I was impressed by the quality of analyses and was pleased to see the use of microprobe and petrographic analyses. While the science seems robust, some changes are necessary before I can recommend this manuscript for publication.

 

Major comments:

1. 13 out of the 52 references in this paper are self-citations. While I understand that self-citation is often necessary, 25% of the references is a bit excessive. Please work to more thoroughly review the literature. In particular, there are a lot of past studies that have investigated alkaline syenite deposits in other regions, which would be useful to include for comparison and also to review in the introduction. Below is the DOI for other paper that is not cited but could potentially be useful/relevant.

          https://doi.org/10.1007/s11631-024-00713-2

2. For a paper about radiation exposure, it surprised me that alpha and beta radiation were not discussed. More nuance should be added to the discussion to consider dose rates of alpha, beta, and gamma at specific distances and how these exposure risks compare with other natural building materials such as granite. If the exposure from this rock would be mostly alpha radiation, for example, could this rock still be used as a building material as long as the public limits exposure within a few cm (by placing furniture in front or avoiding direct contact)?
3. Do these results have any implications for other alkaline syenite deposits around the world? It would be useful to have a sentence or two explaining possible implications and/or limitations for the application of these results to other deposits.
4. Figure 6 needs a bit more explanation. This figure indicates that potassium-40 drives the radiological variance. While this figure is useful, readers need some context as to why this matters for radiation exposure. This figure may be better in the SI.
5. How would radiological hazards change during the erosion process? Would eroded sediments have higher or lower radiation risks (I would likely expect higher since minerals containing radionuclides such as zircon tend to be resistant to erosion)? What might the implications be for communities that could be affected by wind deposition from these sediments?

Minor comments:

I found a paper published in 2024 that appears very similar to the present work, although I have no concerns that the work by Abdel Gawad et al. is independent from their study. The 2024 paper (DOI: https://doi.org/10.1038/s41598-024-59627-x) studied the activity of radionuclides of minerals from the same region of Egypt and concluded that the rocks were safe to use for construction materials. This paper should be cited and it should be clearly stated in the manuscript what differentiates the current study on alkaline syenites from that paper.

Line 189: Why were samples dried at 100 C? Often, soil and sediment samples are dried at 40-50 C to limit mineral transformations (such as from goethite to hematite, which can occur at temperatures greater than 70 C). Please add a sentence to explain.

Figure 3: mineral abbreviations should be explained in caption to improve readability. Even as someone who is familiar with petrography, it still took me a minute to find that Pth represents perthite, for example.

Tables 1-5: Consider plotting the REE abundances in these mineral phases versus bulk chondrite or other magmatic systems (either in the main manuscript or SI). How do the REE compositions of the minerals in this deposit compare with zircon, bastnasite, etc. from other deposits? Investigators who are interested in rare earth extraction could benefit from having these plots. The data is already in the tables, so plotting these results would make them more accessible and increase the impact of this manuscript.

Figure 6b: The labels on the left side of the plot are unreadable. Please fix.

Author Response

Responses to Reviewer’s Comments
We sincerely appreciate the reviewer's professional feedback on our manuscript, as it provides valuable insights that greatly contribute to enhancing its quality. Carefully considering each comment, we have diligently revised and improved the manuscript, aiming to address all pertinent points raised. 
We have responded to the comments point by point with red font in the revised manuscript. 
Reviewer 4:
Major comments:
Comment 1: 13 out of the 52 references in this paper are self-citations. While I understand that self-citation is often necessary, 25% of the references is a bit excessive. Please work to more thoroughly review the literature. In particular, there are a lot of past studies that have investigated alkaline syenite deposits in other regions, which would be useful to include for comparison and also to review in the introduction. Below is the DOI for other paper that is not cited but could potentially be useful/relevant.
          https://doi.org/10.1007/s11631-024-00713-2 
Response: we have deleted some self-citations (Skublov et al., 2021, Ali et al., 2018; Eliwa et al., 2018) and added the recommended citation (Emad 2024).
Emad, B.M. Alkaline igneous rocks, a potential source of rare metals and radioactive minerals: Case study at Amreit area, south astern Desert, Egypt. Acta Geochim, 2024, https://doi.org/10.1007/s11631-024-00713-2.

Other new advanced citations of rare metals granites have been added to the section References as follows:

[15] Abdelfadil K.M.; Mahdy N.M.; Ondrejka M.; Putiš M. Mineral chemistry and monazite chemical Th–U–total Pb dating of the Wadi Muweilha muscovite pegmatite, Central Eastern Desert of Egypt: constraints on its origin and geodynamic evolution relative to the Arabian Nubian Shield. International Journal of Earth Sciences, 2022, 111, 823–860.
[16] Surour, A.A. Sn-W-Ta-Mo-U-REE mineralizations associated with alkali granite magmatism in Egyptian Nubian Shield. In: Hamimi, Z. Arai, S., Fowler, A., El-Bialy, M.Z., The Geology of the Egyptian Nubian Shield, Regional Geology Reviews, Springer Nature Switzerland, 2021, 593–604. https://doi.org/10.1007/978-3-030-49771-2
[17] Azer, M.K.; Abdelfadil, K.M.; Ramadan, A.A. Geochemistry and petrogenesis of late Ediacaran rare-metal albite granite of the Nubian shield: case study of Nuweibi intrusion, eastern Desert, Egypt. J. Geol. 2019, 127 (6), 665–689.

.[18] Sami, M.; El Monsef, M.A.; Abart, R.; Toksoy-Koksal, F.; Abdelfadil, K.M. Unraveling the genesis of highly fractionated rare metal granites in the Nubian shield via the rare-earth elements tetrad effect, Sr–Nd isotope systematics, and mineral chemistry. ACS Earth Space Chem. 2022, 6, 2368–384. https://doi.org/10. 1021/acsearthspacechem.2c001 25.

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Comment 2: For a paper about radiation exposure, it surprised me that alpha and beta radiation were not discussed. More nuance should be added to the discussion to consider dose rates of alpha, beta, and gamma at specific distances and how these exposure risks compare with other natural building materials such as granite. If the exposure from this rock would be mostly alpha radiation, for example, could this rock still be used as a building material as long as the public limits exposure within a few cm (by placing furniture in front or avoiding direct contact)?

Response: We appreciate the reviewer’s valuable feedback regarding the discussion of alpha and beta radiation dose rates and their implications for exposure risks. However, our study specifically focuses on the gamma radiation emitted from the investigated alkaline syenite and its associated radiological hazards. The assessment was conducted using high-purity germanium (HPGe) gamma spectrometry, which is well-suited for evaluating the gamma-emitting radionuclides (238U, 232Th, and 40K) and their contributions to external radiation exposure.
While alpha and beta radiation can be significant in certain exposure scenarios, their primary health impact arises from internal exposure through inhalation or ingestion rather than direct external exposure. Given that our study is centered on the external gamma dose assessment and its implications for radiological safety, we have not included an analysis of alpha and beta dose rates. Moreover, the radiological hazard indices calculated, such as the radium equivalent activity (Raeq), absorbed dose rate, annual effective dose, and excess lifetime cancer risk (ELCR), are primarily derived from gamma radiation measurements and international safety guidelines.
Regarding the potential use of these rocks as a building material, our findings already indicate that the gamma radiation levels exceed recommended safety thresholds, particularly for indoor applications. As such, even without considering alpha and beta contributions, the investigated rock is not recommended for construction use due to its elevated radiological risks.
We hope this explanation clarifies our approach and rationale, and we sincerely appreciate the reviewer's input in strengthening the manuscript.

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Comment 3: Do these results have any implications for other alkaline syenite deposits around the world? It would be useful to have a sentence or two explaining possible implications and/or limitations for the application of these results to other deposits.

Response: We appreciate the reviewer’s suggestion to clarify the broader implications of our findings for other alkaline syenite deposits worldwide. While our study focuses on the Nikeiba alkaline syenite, similar rock types occur globally and are often enriched in uranium (U), thorium (Th), and potassium (K). Given the observed elevated radioactivity levels, our findings highlight the necessity of site-specific radiological assessments before considering alkaline syenite as a building material. However, it is important to note that the radioactive element concentrations can vary significantly due to differences in mineralogy, geological history, and local geochemical conditions. Thus, while our results provide a valuable reference, they should not be directly extrapolated to all alkaline syenite deposits without further investigation. Future studies should conduct detailed gamma spectrometry, mineralogical characterization, and dose assessments to ensure accurate evaluations of radiological safety.

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Comment 4:  Figure 6 needs a bit more explanation. This figure indicates that potassium-40 drives the radiological variance. While this figure is useful, readers need some context as to why this matters for radiation exposure. This figure may be better in the SI.
Response: The more explanations is added in the manuscript as follows " The statistical analysis (Figure 6) indicates that 40K is the primary contributor to the observed radiological variance in the studied alkaline syenite samples. In contrast to 238U and 232Th, which are predominantly found in accessory minerals such as thorite, monazite, and zircon, 40K is a significant component of rock-forming minerals like feldspars and micas. Consequently, its concentration is considerably higher and more homogeneously distributed in the rock matrix. Although 40K exhibits a lower radiotoxicity compared to uranium and thorium, it contributes significantly to the external gamma dose due to its relatively high energy gamma emissions (1460 keV). This underscores the need to consider its role in radiological risk assessments of alkaline syenite and similar rock types. While 40K does not pose significant internal exposure risks unless ingested or inhaled in substantial amounts, its contribution to ambient gamma radiation should not be overlooked, particularly in indoor environments where prolonged exposure may increase cumulative dose rates. In light of the statistical findings, future radiological assessments of building materials derived from alkaline syenite should evaluate 40K contributions alongside uranium- and thorium-related hazards to provide a more comprehensive risk assessment."
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Comment 5: How would radiological hazards change during the erosion process? Would eroded sediments have higher or lower radiation risks (I would likely expect higher since minerals containing radionuclides such as zircon tend to be resistant to erosion)? What might the implications be for communities that could be affected by wind deposition from these sediments?
Response: The main objective of the present work is alkaline syenite that could be affected by erosion and/or weathering processes along few centimeters on the surface. The collected samples of the present work selected far from the eroded surface. This work does not investigate sediments but magmatic intrusion.
This magmatic system is affected by the hydrothermal alteration processes including albitization, silicification, episyenitization, fluoritization and hematitization as recorded by 
Abdel Gawad, A.E. Geology and radioelements potentialities of unconformable basement-sedimentary rocks at G. Nikeiba and G. Fileita areas, south Eastern Desert, Egypt. Unpublished PhD thesis, Faculty of Science, Minufiya University, Egypt, 2011, 141 p. 
Zircon could be affected by different hydrothermal alteration as mentioned by many authors, for ex. Abdalla et al., 2008; El–Bialy and Ali 2013; Skublov et al., 2021, ………………… 
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Minor comments:
Comment 6:  I found a paper published in 2024 that appears very similar to the present work, although I have no concerns that the work by Abdel Gawad et al. is independent from their study. The 2024 paper (DOI: https://doi.org/10.1038/s41598-024-59627-x) studied the activity of radionuclides of minerals from the same region of Egypt and concluded that the rocks were safe to use for construction materials. This paper should be cited and it should be clearly stated in the manuscript what differentiates the current study on alkaline syenites from that paper.
Response: Abdel Gawad et al. 2024: stated that the higher concentrations were identified in syenogranite, alkali feldspar granite and quartz syenite, while lower levels were observed in metavolcanics, tonalite-granodiorite and Nubian sandstone.
The main objective is studding the distribution of radionuclides in granites (both syenogranite and alkali feldspar granite).
Minerals have been identified using Environmental Scanning Electron Microscope (ESEM) integrated with an Energy Dispersive Spectrometer (EDS) unit (Philips XL 30 ESEM) at NMA of Egypt.
The average activity concentration of radionuclides in the granites (syenogranite and alkali feldspar granite) 238U (74±16 Bq kg-1), 232Th (80±15 Bq kg-1), and 40K (893±122 Bq kg-1) exceeded worldwide averages. The higher concentration is coincided with the presence of minerals harboring radioelements as thorite, monazite and zircon suggests these granites are unsuitable for construction.
We have add citation Abdel Gawad et al. 2024 in section References
Abdel Gawad, A.E.; Hammam, H.F.; Abd El Rahman, R.M.; Hanfi, M.Y. Environmental impact assessment of granites bearing rare metals mineralization utilizing airborne gamma‑ray spectrometric data, Egypt. Journal of Radioanalytical and Nuclear Chemistry, 2024, https://doi.org/10.1007/s10967-024-09852-5
The present work is completely different from the above citation:
The main objective of the present study provide micro-chemical analyses (EPMA) of the investigated rare metals mineralization in the alkaline syenite at Nikeiba. Furthermore, this work strives to measure the natural radionuclides concentration and their related environmental hazards from the alkaline syenite rocks. The radioactive risk is accomplished through many radiological hazard indices.
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Comment 7: Often, soil and sediment samples are dried at 40-50 C to limit mineral transformations (such as from goethite to hematite, which can occur at temperatures greater than 70 C). Please add a sentence to explain.
Response: Thank you for your recommendation. The following text will explain the authors used the temperature of 100 oC " Prior to the implementation of radiometric analysis, the samples were subjected to a drying process. This process was conducted at a temperature of 100°C for a duration of 72 hours. The drying temperature was selected to ensure the complete removal of moisture while minimizing the potential loss of volatile radionuclides, which can affect accurate gamma spectrometric measurements. While lower drying temperatures (40–50°C) are often used to prevent mineral phase transformations, the primary objective here was to achieve stable and reproducible radiometric conditions. Since the study focuses on gamma-emitting radionuclides (238U, 232Th, 40K), rather than mineralogical changes, this drying protocol was deemed appropriate."

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Comment 8: Figure 3: mineral abbreviations should be explained in caption to improve readability. Even as someone who is familiar with petrography, it still took me a minute to find that Pth represents perthite, for example.
Response: All mineral abbreviation have been added in section geology, petrography and mineral chemistry.
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Comment 9: Tables 1-5: Consider plotting the REE abundances in these mineral phases versus bulk chondrite or other magmatic systems (either in the main manuscript or SI). How do the REE compositions of the minerals in this deposit compare with zircon, bastnasite, etc. from other deposits? Investigators who are interested in rare earth extraction could benefit from having these plots. The data is already in the tables, so plotting these results would make them more accessible and increase the impact of this manuscript.
Response: we have two types of minerals bearing REEs (a) LREEs (b) HREEs. By utilizing chonderite normalized REE patterns for every mineral is not useful, due to the most REEs are not recorded in each mineral. So, LREE minerals lost the most group of HREEs, and the same as in HREE minerals lost the most group of LREEs.
Plotting LREE and/or HREE alone do not show any sign of chonderite normalized patterns. 
As we know the 15 lanthanide elements could be useful for the chonderite normalized REE patterns, in order to compare between the LREE with HREE.  
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Comment 10: Figure 6b: The labels on the left side of the plot are unreadable. Please fix.
Response: This is due to the overlap between the radiological parameters of the correlations. 
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Many thanks for your constructive comments, effort and suggestion  

Round 2

Reviewer 4 Report

Comments and Suggestions for Authors

Thank you for making many of the suggested changes and for the detailed approach to comments. This manuscript is almost ready for publication and I do not need to see this document again.

I would like to request that the authors fix the following minor typos/phrasing before the final version of this manuscript is published:

Line 21: change "most predominance" to "most predominant"

Line 55: change "rare metals mineralization" to "rare metal mineralization"

Line 66: change "has great interest from" to "is of great interest to"

Lines 78-79: change "is accomplished" to "is determined"

Line 96: change "mostly predominated" to "mostly predominant"

Line 111: change "It is" to "The alkaline syenite is" since it is unclear what it is referring to in this case.

Line 151: change "comprising15 kV" to "including a 15 kV"

Line 205: change "activity" to "activities"

Line 329: remove "it is obvious to mention herein"

Lines 360-361: change "is recorded as minor amounts," to "is present as a minor component"

Lines 454-455: remove "This discrepancy underscores a worrisome trend, as" since the term worrisome is subjective and, thus, should be avoided.

Line 489: change "thorium concentration bears" to "thorium concentrations bear"

Line 520: change "rare metals mineralization" to "rare metal minerals"

Author Response

Responses to Reviewer’s Comments
We sincerely appreciate the reviewer's professional feedback on our manuscript, as it provides valuable insights that greatly contribute to enhancing its quality. Carefully considering each comment, we have diligently revised and improved the manuscript, aiming to address all pertinent points raised. 
We have responded to the comments point by point with BLUE font in the revised manuscript. 
Reviewer 4:
Thank you for making many of the suggested changes and for the detailed approach to comments. This manuscript is almost ready for publication and I do not need to see this document again.
I would like to request that the authors fix the following minor typos/phrasing before the final version of this manuscript is published:
Response: We appreciate the reviewer’s valuable feedback. All required corrections are done in the manuscript.
Comment 1: Line 21: change "most predominance" to "most predominant"
Response:  Done.
Comment 2: Line 55: change "rare metals mineralization" to "rare metal mineralization"
Response:  Done.
Line 66: change "has great interest from" to "is of great interest to"
Response:  Done.
Comment 3: Lines 78-79: change "is accomplished" to "is determined"
Response:  Done.
Comment 4: Line 96: change "mostly predominated" to "mostly predominant"
Response:  Done.
Comment 5: Line 111: change "It is" to "The alkaline syenite is" since it is unclear what it is referring to in this case.
Response:  Done.
Comment 6: Line 151: change "comprising15 kV" to "including a 15 kV"
Response:  Done.
Comment 7: Line 205: change "activity" to "activities"
Response:  Done.
Comment 8: Line 329: remove "it is obvious to mention herein"
Response:  Done.
Comment 9: Lines 360-361: change "is recorded as minor amounts," to "is present as a minor component"
Response:  Done.
Comment 10: Lines 454-455: remove "This discrepancy underscores a worrisome trend, as" since the term worrisome is subjective and, thus, should be avoided.
Response:  Done.
Comment 11: Line 489: change "thorium concentration bears" to "thorium concentrations bear"
Response:  Done.
Comment 12: Line 520: change "rare metals mineralization" to "rare metal minerals"
Response:  Done.
Many thanks for your constructive comments, effort and suggestion