Assessment of Radiological Risks due to Indoor Radon, Thoron and Progeny, and Soil Gas Radon in Thorium-Bearing Areas of the Centre and South Regions of Cameroon
, Bineng Guillaume Samuel 1,2, Chutima Kranrod 4, Yasutaka Omori 4, Masahiro Hosoda 4,5, Saïdou 1,2,* and Shinji Tokonami 4
Akbar Abbasi
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe manuscript is a novel contribution about the radiological characterization and risk assessment of radon and thoron soil gas and indoor in an interesting thorium bearing areas of Cameroon. The analyses performed for the investigation of radionuclide content and hazard indexes are appropriate, together with the graphs and tables. The introduction is good. The results are well compared with the worldwide limits but need more comparisons with the similar results from the other Countries. The abstract and conclusions fully hit the target and the results obtained in the work, and reflect the overall idea of the manuscript. The paper is well conceived. The work is a good and hard work. The manuscript is a significant novel contribution. The title is appropriate and clear.
The main goal of this work is clear and the activities done to fulfill the goal are well described. The analysis on the data is clear and complete, using appropriate statistical methodology. The main output is clearly described and presented in a good form. The tables and figures and captions are clear and understandable.
Tables 8,9,10 need to be implemented with the comparison with similar results from other Countries, as done for the Table 7 that requires also the comparison with at least another European Country. Please add the following references to implement the tables and also to get ideas to improve the discussion:
- https://doi.org/10.1016/j.net.2020.03.013
- https://doi.org/10.1140/epjp/s13360-023-04452-w
- https://doi.org/10.1016/j.radmp.2021.07.002
- https://doi.org/10.1016/j.conbuildmat.2017.11.116
- https://doi.org/10.3390/app11135809
The manuscript is fully suitable for the Journal, and perfectly falls into the aims of the Journal. The topic is of interest to readers of the Journal. In conclusion, I recommend the manuscript to be accepted for publication only after the modifications listed above.
Author Response
RESPONSES OF AUTHORS TO REVIEWER 1.
COMMENT
Tables 8,9,10 need to be implemented with the comparison with similar results from other Countries, as done for the Table 7 that requires also the comparison with at least another European Country. Please add the following references to implement the tables and also to get ideas to improve the discussion:
RESPONSE
Line 608
That have been done and the reference https://doi.org/10.1016/j.radmp.2021.07.002 has been put in the manuscript.
Reviewer 2 Report
Comments and Suggestions for AuthorsTitle: Radiological risk assessment due to indoor radon, thoron and progeny, and soil gas radon in the thorium bearing areas of Centre and South regions of Cameroon
Submission ID: atmosphere-2690829
Journal: Atmosphere
In this study, “Radiological risk assessment due to indoor radon, thoron and progeny, and soil gas radon in the thorium bearing areas of Centre and South regions of Cameroon” was investigated radon-thoron discriminative detectors (RADUET), while thoron progeny monitors measured the equilibrium equivalent thoron concentration (EETC). Radon in soil concentrations were determined using MARKUS 10 detector.. The title is good and research results can be published but before publishing there are some major comments that authors can be consider them and revise the manuscript.
1- Title need to revise and written more clear
2- All of text needs to revise by English native language.
3- In the “Experimental Techniques” section add MDL (minimum detection limit) using for calculations with following references method.
4- Figure 2 is not needed. Remove it.
5- All figure need to increases the resolution.
6- Add a statistical analyze for your experiment measurements results.
6- Introduction section and results and discussion section need to rewrite by using following new papers in this research filed. (The authors can read them and use those papers to improve his manuscript in international level.)
Windcatcher Ventilation Computation and Indoor 222Rn Concentration in Traditional Adobe Houses, Radiation Protection Dosimetry
The manuscript can be publishing after revising and using the above papers results.
Comments on the Quality of English Language
All of text needs to revise by English native language.
Author Response
RESPONSES OF AUTHORS TO REVIEWER 2
COMMENT
Title need to revise and written more clear
RESPONSE
Line 3
Title has been revised.
COMMENT
All of text needs to revise by English native language.
RESPONSE
The text has been revised by English native language
COMMENT
In the “Experimental Techniques” section add MDL (minimum detection limit) using for calculations with following references method.
RESPONSE
Line 122 and 176
The lower detection limits (DLs) of RADUESTs were determined to be 3 Bqm-3 for radon and 4 Bqm-3 for thoron [Chen, J., Tokonami, S., Sorimachi, A., Takahashi, H., & Falcomer, R. (2007). Preliminary results of simultaneous radon and thoron tests in Ottawa. Radiation Protection Dosimetry, 130(2), 253–256. doi:10.1093/rpd/ncm503]). For MARKUS 10 detector, the detection limit of 0.1 kBq/m3 can be offered on request. These have been added in the manuscript.
COMMENT
Figure 2 is not needed. Remove it.
RESPONSE
Thank you for the suggestion.
COMMENT
All figure need to increases the resolution.
RESPONSE
Figure resolution has been improved
COMMENT
Add a statistical analysis for your experiment measurements results.
RESPONSE
Line 344
The statistical analyse of the results has been added to the manuscript: The statistical analysis was carried out using Origin Pro, to illustrate the data distribution, measures of central tendency, and variability of the measured parameters (indoor radon/thoron, radon and thoron progeny and radon in soil gas) in histogram and box plots. The box plot graphically depicts numerical data through their quantiles. The line inside each box represents the median (Q2 or second quartile), while the lower and upper edges of the box are the Q1 and Q3 (first and third quartile) respectively. The Shapiro-Wilk test was applied to test the normality of soil gas radon measurements.
COMMENT
Introduction section and results and discussion section need to rewrite by using following new papers in this research filed. (The authors can read them and use those papers to improve his manuscript in international level.)
RESPONSE
These sections have been revised by using the research field new paper.
Reviewer 3 Report
Comments and Suggestions for AuthorsThis article presents measurements of radon and thoron concentrations in soils and residential spaces in central and south Cameroon. Authors have used two compact instruments for these measurements. The accumulated doses and risk factors calculated for progenies of thoron and radon were found to be higher than the global averages, and pose questions for future research. The paper is suitable for the journal but requires some major revision.
Some line wise comments:
- 82) why is a depth of 0.7 m used for soil concentration measurements? Is it a standardized procedure? One would expect significant variation in the number depending on the depth of sampling radon gas.
- What is the detection limit of Markus 10 type detector?
- 155) 1 to 2 m above ground is a wide range of sampling height. Could you provide median sampling height? And why does this vary?
- 188) what exactly do you mean by “a measurement period”? This needs some specificity.
- 213) what is the expected range of absolute values of the FTn factor?
- 238) What does the symbol “T” stand for?
- 288) It is not clear what kinds of diffusion is being discussed in this equation. Could you please add some more descriptions?
- Authors have not discussed Fig 4a in the text at all.
- 301) it seems that the cited paper [32] does not exactly present a world average value. It should be clarified if it is actually a value representing worldwide GM?
- 313) authors talk about some recommendations made to dwellers of the surroundings to reduce the progeny concentrations. It will be valuable to add some details of the proposed methods.
- 328) “follows lognormal” doesn’t look strictly correct. It will be better to put down the figures of merit of the fit, and let the reader judge for themselves.
- Have you found any correlations between the Ra and Ta concentrations?
- 357) “slightly higher” seems slightly incorrect. We are talking about 5 times higher here.
- 358) can you elaborate how you are expecting to explain the higher indoor radon concentrations based on the “geology of the soil”. This needs describing, and reference to previous studies.
- Figure 5) Change the shadings to something coarser and visually clear.
- 391) Can this observation be connected to maybe some recent deposition events in the locality?
- What is the source of data Frn=0.4? This needs to be described.
- Figure 6) left, two green colored bars are confusing visually. Change it to something more distinct or to some coarse shading. Right figure, the legend is not readable easily—use larger fonts.
- A clear tendency is visible in the results: Tnp>Rnp>Tn>Rn. You could mention this.
- 436) Can you correlate the Bq values of Rn and Tn directly along with the correlation between inhalation doses?
- 447) what are the possible reasons for this observation in Cameroon: the prominence of thoron progenies?
- Authors need to describe the chosen values of permeability factor: 10-11 to 10-13. Also, what are the units?
- 491) what is the relevance of high GRP values? Its relevance needs to be explained in the article.
- 474) what do you mean by “distinct characteristics rock and soil properties”, this is unclear.
- Table 7) it seems for both Cameroon data sources, the detector type is same. It will be valuable to check a diverse method of measurement in a future study.
- 501) can you plot the data ad the fitted lognormal distribution for an ease of understanding.
- Authors should move Tabel 8 to after section 3.4, where it is discussed for the first time.
- Authors should mention the conclusion that the median values are higher indoors.
- 530) Swedish classification needs a reference.
- 537) “the area” – is the same locations as studied in the present article? There seems to be a very strong dependence on the location of measurement and so it is important to mention this.
- 550) is it “default” or “average”?
- 561-563) I will not conclude this. The health hazards are not negligible.
- 564) add “except three locations”.
Comments on the Quality of English LanguageEnglish is fine. Some minor editing is required. I can comment at the second round of review if English still has some issues.
Author Response
RESPONSES OF AUTHORS TO REVIEWER 3
COMMENT
82) Why is a depth of 0.7 m used for soil concentration measurements? Is it a standardized procedure? One would expect significant variation in the number depending on the depth of sampling radon gas.
RESPONSE
This depth was chosen according to the Soil Radon Index (SRI) which is an indicator used to estimate the potential risk of given area. It consists of a dimensionless value calculated from measurements of radon concentrations in soil gas at a depth of 0.7 m and the permeability of this soil [Lara, E., Rocha, Z., Palmieri, H. E. L., Santos, T. O., Rios, F. J., & Oliveira, A. H. (2015). Radon concentration in soil gas and its correlations with pedologies, permeabilities and 226Ra content in the soil of the Metropolitan Region of Belo Horizonte – RMBH, Brazil. Radiation Physics and Chemistry, 116, 317–320. doi:10.1016/j.radphyschem.2015.02.017]. In addition this depth was chosen because in these different regions at this time of year the ground is very hard, so it was very difficult for us to get the detector probe into a greater depth.
COMMENT
What is the detection limit of Markus 10 type detector?
RESPONSE
Line 122
The detection limit of Markus 10 type detector is 0.1 kBq/m3
COMMENT
155) 1 to 2 m above ground is a wide range of sampling height. Could you provide median sampling height? And why does this vary?
RESPONSE
Placing the detectors at a height of 1-2 meters helps to capture the average concentration of radon and thoron in the breathing zone of occupants, as these gases tend to be heavier than air and can accumulate closer to the ground. This placement is based on several factors, including the need to ensure accurate measurements and minimize potential interference from nearby objects or surfaces. All monitors were positioned 1.5 m above the floor.
COMMENT
188) what exactly do you mean by “a measurement period”? This needs some specificity.
RESPONSE
Line 227
The specification has been added in the manuscript: a measurement period of about six months
COMMENT
213) what is the expected range of absolute values of the FTn factor?
RESPONSE
The equilibrium factor for thoron is generally expected to be close to unity
COMMENT
238) What does the symbol “T” stand for?
RESPONSE
Line 330
T is the exposure time
COMMENT
288) It is not clear what kinds of diffusion is being discussed in this equation. Could you please add some more descriptions?
RESPONSE
Line 335
Descriptions of diffusion parameters have been added to the manuscript: The exhalation diffusion constant (d) is a parameter that describes the rate at which radon gas moves from the soil into the air. It represents the diffusion process by which radon is released from the soil and transported to the surface, and the eddy diffusion coefficient (D) is a parameter that characterizes the mixing and dispersion of radon gas in the air. It represents the turbulent diffusion process by which radon is dispersed in the atmosphere after it is released from the soil.
COMMENT
Authors have not discussed Fig 4a in the text at all.
RESPONSE
Discussion has been done in line 403-406
COMMENT
301) it seems that the cited paper [32] does not exactly present a world average value. It should be clarified if it is actually a value representing worldwide GM?
RESPONSE
Line 368
The clarification has been added to the manuscript: Lower than the international indoor geometric mean of 45 Bq/m3
COMMENT
313) Authors talk about some recommendations made to dwellers of the surroundings to reduce the progeny concentrations. It will be valuable to add some details of the proposed methods.
RESPONSE
Details of the proposed methods for reducing concentrations have been added to the manuscript: line 381
- increase air flow in your house by opening windows and using fans and vents to circulate air
- seal cracks in floors and walls with plaster caulk, or other materials designed for this purpose
COMMENT
328) “follows lognormal” doesn’t look strictly correct. It will be better to put down the figures of merit of the fit, and let the reader judge for themselves.
RESPONSE
Figures have been improved in the manuscript
COMMENT
Have you found any correlations between the Ra and Ta concentrations?
RESPONSE
There is no correlation between radon and thoron in this study
COMMENT
357) “slightly higher” seems slightly incorrect. We are talking about 5 times higher here.
RESPONSE
Line 430
The slightly has been removed
COMMENT
358) can you elaborate how you are expecting to explain the higher indoor radon concentrations based on the “geology of the soil”. This needs describing, and reference to previous studies.
RESPONSE
Line 432
The description has been added with reference: according to study reported by Bineng et al 2022 Geological maps of study areas shows that the soil and the bedrocks of the uranium and thorium bearing region of Lolodorf con-sists of the rocks and minerals
COMMENT
Figure 5) Change the shadings to something coarser and visually clear.
RESPONSE
Figure 5 has been improved
COMMENT
391) Can this observation be connected to maybe some recent deposition events in the locality?
RESPONSE
This observation of high thoron equilibrium factor values is due firstly to direct measurements of thoron progeny and secondly to soil geology in the various localities
COMMENT
what is the source of data Frn=0.4? This needs to be described.
RESPONSE
FRn is equilibrium factor of radon (UNSCEAR 2008)
COMMENT
Figure 6) left, two green colored bars are confusing visually. Change it to something more distinct or to some coarse shading. Right figure, the legend is not readable easily—use larger fonts.
RESPONSE
Figure 6 left and right have been improved
COMMENT
A clear tendency is visible in the results: Tnp>Rnp>Tn>Rn. You could mention this.
RESPONSE
Line 570
This tendency has been added to the manuscript: A higher clear tendency of the annual effective dose due to progeny of indoor radon and thoron is visible in the results: Tnp>Rnp>Tn>Rn.
COMMENT
436) Can you correlate the Bq values of Rn and Tn directly along with the correlation between inhalation doses?
RESPONSE
The inhalation dose refers to the amount of radiation that a person receives through the inhalation of radon and thoron gases and their decay products. The correlation between inhalation doses of radon and thoron can be influenced by several factors, including the concentrations of radon and thoron, the duration of exposure, and the ventilation rate of the indoor environment. It is recommended to conduct individual dose assessments based on measurements of radon and thoron concentrations and other relevant factors
COMMENT
447) what are the possible reasons for this observation in Cameroon: the prominence of thoron progenies?
RESPONSE
Direct measurements of thoron progeny concentrations have been found to be important for accurate assessments and dose estimations
COMMENT
Authors need to describe the chosen values of permeability factor: 10-11 to 10-13. Also, what are the units?
RESPONSE
Line 310
is the soil gas permeability measured in m2, which we assumed it for bare earth varying from 10-11 to 10-13 [UNSCEAR 1993]
COMMENT
491) what is the relevance of high GRP values? Its relevance needs to be explained in the article
RESPONSE
Line 616
This explanation has been added in article: Bikoue is located at a place where anomalies of uranium and thorium have been detected (Bineng et al. 2019)
Bineng GS, Saïdou, Hosoda M, Tchuente Siaka YF, Akata N, Simplice FT, et al. External radiation exposure to the public using car-borne survey method in the uranium and thorium bearing region of Lolodorf, Cameroon. Rad Environ Med. (2019) 9:1.
COMMENT
474) what do you mean by “distinct characteristics rock and soil properties”, this is unclear.
RESPONSE
Line 596
An explanation has been added in article to the effect that : This area is known as having uranium and thorium anomalies at some specific places ( Bineng et al. 2020)
Bineng, G.S.; Saïdou; Tokonami, S.; Hosoda, M.; Tchuente, S.Y.F.; Issa, H.; Suzuki, T.; Kudo, H.; Bouba, O. The Importance of Direct Progeny Measurements for Correct Estimation of Effective Dose Due to Radon and Thoron. Front. Public Health 2020, 8, 17
COMMENT
Table 7) it seems for both Cameroon data sources, the detector type is same. It will be valuable to check a diverse method of measurement in a future study.
RESPONSE
We will do that in the future study
COMMENT
501) can you plot the data ad the fitted lognormal distribution for an ease of understanding.
RESPONSE
COMMENT
Authors should move Tabel 8 to after section 3.4, where it is discussed for the first time.
RESPONSE
Line 646
That has been done
COMMENT
Authors should mention the conclusion that the median values are higher indoors.
RESPONSE
Line 664
According to external effective dose due to gamma rays, the median values are higher indoors.
COMMENT
530) Swedish classification needs a reference.
RESPONSE
Reference has been added
COMMENT
537) “the area” – is the same locations as studied in the present article? There seems to be a very strong dependence on the location of measurement and so it is important to mention this.
RESPONSE
Line 750
This sentence has been reformulated as follow: the area in Adamawa region
COMMENT
550) is it “default” or “average”?
RESPONSE
The mean annual effective dose
COMMENT
561-563) I will not conclude this. The health hazards are not negligible.
RESPONSE
Line 778
The sentence has been improved as follow: the health hazards are not negligible
COMMENT
564) add “except three locations”.
RESPONSE
Line 781
That has been performed in the manuscript: The results show that the radiological risk due to indoor and outdoor environment in the study area is low following public exposure indoors and outdoors except three locations.
Reviewer 4 Report
Comments and Suggestions for AuthorsThe presented manuscript describes the results of radon measurements in Cameroon with additional discussion about it. The experimental part of the manuscript is of good quality and I have no significant comments. Whole methodology of radon measurement is excellent, and the paper can be refereed as a good standard for others. I have, however, some comments to other items (like radon risk assessment) or data analysis.
1. "Natural and man-made radionuclides can enter the human body, causing damage effects and leading to health risk." - this is very strong statement which inform the public that all radiation is harmful - which is not the case (see next comments)
2. "Then radon has been identified as the second leading cause of lung cancer after tobacco smoking" - see also my previous comment.
It is true that due to international standards and regulations, radon is find as a popular carcinogen. Also some pooled analyses showed that there is some risk-radon correlation, however, it is hard to determine this finding for lowest concentrations of this radioactive gas. Therefore, many studies, like popular 13 European radon study, assumed linear relationship and exptrapolated risk from medium and high concetrations to the lowest ones (by the way, there is no place on Earth with zero radon concentration to verify that extrapolation). This is a neverending discussion concering the so called "problem of low doses".
We all know that ICRP, IARC and WHO defined radon as a carcinogenic substance even for low concentrations, indeed. They are, however, technical and political bodies, not scientific ones. Therefore, I recommend to discuss some pure scientific papers in this matter. Especially, the ones which show different conclusions to have much wider point of view, for example:
- Thompson et al. "Case–control study of lung cancer risk from residential radon exposure in Worcester County, Massachusetts". Health Physics, 2008
- Dobrzynski et al. "Meta-analysis of thirty-two case–control and two ecological radon studies of lung cancer", Journal of Radiation Research, 2018
- Scott "Residential radon appears to prevent lung cancer". Dose-Response, 2011
- Becker "Health effects of high radon environments in Central Europe: another test for the LNT hypothesis?" Nonlinearity Biol Toxicol Med 2003
and some others. In my opinion the proper scientific study shall contain wide discussion with all known studies and results, especially with the ones which present different conclusions. Therefore I highly recommend to add the discussion with the scientific papers which show no risk increase. Of course you do not need to agree with them but you should discuss and argue why your study and your results are stronger, for example.
3. "For stochastic effects from low-dose background radiation, ICRP 103 suggested the value of 0.057 for the public exposure" - please note, that ICRP suggests different risk factors for different tissues and different radiation sources. Radon is specific stressor to lungs which, in my opinion, is hard to compare with standard ICRP factors. I suggest to give a strong rationale why this factor was selected by the authors, and why applied to such small radon doses (ICRP are dedicated for much higher doses).
4. Figure 4, plots (c) and (d) - the Gaussian fit, which is presented by authors, is rather a poor adjust to the data. I would suggest to discuss other curves, like log-normal or Poissonian.
5. "The indoor and outdoor ELCR values due to gamma absorbed dose rate range from 0.001×10-3 to 0.006×10-3 with a mean value of 0.003×10-3 and from 0.001×10-3 to 0.006×10-3 with a mean value of 0.002×10-3 respectively" - firstly, please put all "-3" into upper case. Secondly, this is a mentioned problem of low dose risk assessment.
Based on comments which I described previously, the Authors should be very carefuly when presenting such a low-dose risk assessment. For example, the Authors use the ICRP model and their own measurements to determine how dangerous is a dose from radon. But it is impossible to determine real risk (if any) in that situation because ICRP models are not (?) dedicated to radon. Such a risk assessment is in fact not estimation, not measurement, but assumption based on the assumed dose-response ICRP model. This should be clearly stated and discussed, I think.
To conclude my review: the paper is important and generally well written. I recommend to publish it after some review up to items mentioned above.
Author Response
RESPONSES OF AUTHORS TO REVIEWER 4
COMMENT
- "Natural and man-made radionuclides can enter the human body, causing damage effects and leading to health risk." - this is very strong statement which inform the public that all radiation is harmful - which is not the case (see next comments)
RESPONSE
More details have been added to the manuscript
COMMENT
- "Then radon has been identified as the second leading cause of lung cancer after tobacco smoking" - see also my previous comment.
COMMENT
It is true that due to international standards and regulations, radon is find as a popular carcinogen. Also some pooled analyses showed that there is some risk-radon correlation, however, it is hard to determine this finding for lowest concentrations of this radioactive gas. Therefore, many studies, like popular 13 European radon study, assumed linear relationship and exptrapolated risk from medium and high concetrations to the lowest ones (by the way, there is no place on Earth with zero radon concentration to verify that extrapolation). This is a neverending discussion concering the so called "problem of low doses".
RESPONSE
More details have been added to the manuscript
COMMENT
We all know that ICRP, IARC and WHO defined radon as a carcinogenic substance even for low concentrations, indeed. They are, however, technical and political bodies, not scientific ones. Therefore, I recommend to discuss some pure scientific papers in this matter. Especially, the ones which show different conclusions to have much wider point of view, for example:
-Thompson et al. "Case–control study of lung cancer risk from residential radon exposure in Worcester County, Massachusetts". Health Physics, 2008
- Dobrzynski et al. "Meta-analysis of thirty-two case– control and two ecological radon studies of lung cancer", Journal of Radiation Research, 2018
- Scott "Residential radon appears to prevent lung cancer". Dose-Response, 2011
- Becker "Health effects of high radon environments in Central Europe: another test for the LNT hypothesis?" Nonlinearity Biol Toxicol Med 2003
RESPONSE
The discussion has been added to the manuscript in relation to the articles cited
COMMENT
and some others. In my opinion the proper scientific study shall contain wide discussion with all known studies and results, especially with the ones which present different conclusions. Therefore I highly recommend to add the discussion with the scientific papers which show no risk increase. Of course you do not need to agree with them but you should discuss and argue why your study and your results are stronger, for example
RESPONSE
COMMENT
- "For stochastic effects from low-dose background radiation, ICRP 103 suggested the value of 0.057 for the public exposure" - please note, that ICRP suggests different risk factors for different tissues and different radiation sources. Radon is specific stressor to lungs which, in my opinion, is hard to compare with standard ICRP factors. I suggest to give a strong rationale why this factor was selected by the authors, and why applied to such small radon doses (ICRP are dedicated for much higher doses).
RESPONSE
Thank you for this comment for its adding value.
COMMENT
- Figure 4, plots (c) and (d) - the Gaussian fit, which is presented by authors, is rather a poor adjust to the data. I would suggest to discuss other curves, like log- normal or Poissonian.
RESPONSE
Figure has been improved
COMMENT
- "The indoor and outdoor ELCR values due to gamma absorbed dose rate range from 0.001×10-3 to 0.006×10-3 with a mean value of 0.003×10-3 and from 0.001×10-3 to 0.006×10-3 with a mean value of 0.002×10-3 respectively" - firstly, please put all "-3" into upper case. Secondly, this is a mentioned problem of low dose risk assessment.
RESPONSE
Reformulated
COMMENT
Based on comments which I described previously, the Authors should be very carefuly when presenting such a low-dose risk assessment. For example, the Authors use the ICRP model and their own measurements to determine how dangerous is a dose from radon. But it is impossible to determine real risk (if any) in that situation because ICRP models are not (?) dedicated to radon. Such a risk assessment is in fact not estimation, not measurement, but assumption based on the assumed dose-response ICRP model. This should be clearly stated and discussed, I think.
RESPONSE
The discussion has been done in the manuscript.
Round 2
Reviewer 3 Report
Comments and Suggestions for AuthorsSampling depth of 0.7 m : the response sounds good. I would suggest updating the manuscript to reflect this methodology, with the cited reference
Figure 4) I would keep the fitting of lognormals as in v1 of the manuscript. My suggestion was to add in the text the fitting parameters, and let the readers judge if it looks significant or not. I would have suggested adding the fit to Figure 8 as well, for visual guidance.
Author Response
RESPONSES OF AUTHORS TO REVIEWER 3.
COMMENT
Sampling depth of 0.7 m : the response sounds good. I would suggest updating the manuscript to reflect this methodology, with the cited reference
RESPONSE
Line 90
The manuscript has been updated as follows: “ according to the Soil Radon Index (SRI) which is an indicator used to estimate the potential risk of given area. It consists of a dimensionless value calculated from measurements of radon concentrations in soil gas at a depth of 0.7 m and the permeability of this soil [11].” And reference has been cited.
COMMENT
Figure 4) I would keep the fitting of lognormals as in v1 of the manuscript. My suggestion was to add in the text the fitting parameters, and let the readers judge if it looks significant or not. I would have suggested adding the fit to Figure 8 as well, for visual guidance.
RESPONSE
Figures 4 and 8 have been improved in the manuscript
