Investigating Radon Concentrations in the Cango Cave, South Africa

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Refer to the attached file

Comments for author File: Comments.pdf

Author Response

[Comment 1] Introduction: Stated to ensure that the reader understands the specific objectives of the study from the outset.

Response 1: The objectives were added in the Introduction.

 

[Comment 2] Literature Review: The manuscript references key studies related to atmospheric processes, but there could be more emphasis on recent developments in the field.

Response 2: The most recent measurement and assessment of the Cango is included in the discussions.

 

[Comment 3] Methods: Describe instrument calibration and the specific parameters measured.

Response 3: Calibration and the specific parameters were added.

 

[Comment 4] Results: Some of the figures could be more informative with additional labelling or explanation.

Response 4: Several additional information was added to some of the figures.

 

[Comment 5] Statistical Analysis: The explanation of the statistical techniques used could be expanded.

Response 5: Systematic statistical errors were added.

 

[Comment 6] Discussion: Some claims could be more thoroughly supported with references to the data or previous studies

Response 6: Several additions to the Discussion were made.

 

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript presents the subject of the study in a precise, structured and relevant manner. The cited sources are relevant, but at the same time, they could be significantly supplemented; many of the cited works are over 20 years old, which can be explained by objective reasons and a long history of studying the issue of radon content in the air of caves. The design of the experiment sounds scientific, but actually includes single measurements, which reduces the hypothesis to a comparison with other works, most of which present systematic measurements in different periods, including with different climatic conditions. As a result, a direct comparison of the data is not entirely correct. The graphic design is well done, the figures and tables reflect the data obtained.

Remarks:

The results of the study represent a single measurement of radon volume activity. It is not possible to estimate possible fluctuations in radon concentration and fully assess the average annual level. Also, the information is insufficient to estimate the average radiation dose for a tourist visit and the possible level of professional radiation for those working in the cave. Conclusions about the danger to humans cannot be formulated based on single measurements. In fact, the volume of the presented study is closer to the format of a separate message than a separate research paper.

Data on the detailed dynamics of air flows are not presented, the presence of additional airways communicating with the surface is not indicated and this fact is objectively difficult or even impossible to establish. In such a situation, conducting a set of measurements in different periods of the year would allow us to draw a conclusion about the air movement in the cave and the dynamics of VAR.

Section 2.1. Contains not only the measurement methodology, but also a lengthy description, perhaps it is worth highlighting separately.

The manuscript can be supplemented with data and significantly increased scientifically soundness.

Author Response

[Comment 1] The results of the study represent a single measurement of radon volume activity. It is not possible to estimate possible fluctuations in radon concentration and fully assess the average annual level.

Response 1: The results of this study were based on autumn measurements were not generalized to a full year cycle.  The conclusion however states that previous summer measurements compare well with the autumn measurements of this study.

 

[Comment 2] The information is insufficient to estimate the average radiation dose for a tourist visit and the possible level of professional radiation for those working in the cave.

Response 2: The study's objective was not to predict the average radiation dosage for tourists and guides, but rather to quantify and visualize the radon concentrations in Cango I.

 

[Comment 3] Conclusions about the danger to humans cannot be formulated based on single measurements. In fact, the volume of the presented study is closer to the format of a separate message than a separate research paper.

Response 3: The study does not provide a direct conclusion regarding radon exposure or danger; rather, it merely speculates on potential mitigation strategies for elevated radon concentrations.

 

[Comment 4] Data on the detailed dynamics of air flows are not presented, the presence of additional airways communicating with the surface is not indicated and this fact is objectively difficult or even impossible to establish. In such a situation, conducting a set of measurements in different periods of the year would allow us to draw a conclusion about the air movement in the cave and the dynamics of VAR.

Response 4: The recommendation to perform airflow measurements throughout the year is noted. The trends in temperature, radon concentrations and humidity however suggested still suggest airways in the latter part of the cave. Consensually the speculation regarding alternative openings.

 

[Comment 5] Section 2.1. Contains not only the measurement methodology, but also a lengthy description, perhaps it is worth highlighting separately.

Response 5: Highlighted as requested.

 

[Comment 6] The manuscript can be supplemented with data and significantly increased scientifically soundness.

Response 6: This recommendation is noted.

Reviewer 3 Report

Comments and Suggestions for Authors

It is crucial to evaluate the radon levels in closed environments or spaces, such as caves, that are inhabited by people. It is necessary to take the necessary steps to lower radon exposure and, therefore, the hazards involved. The study examines the levels of radon in Cango, a well-known tourist destination in the Cango Cave that receives a lot of traffic from tourists and the tour guides who accompany them. The survey was carried out in mild fall weather. The research made an effort to ventilate the cave and offered data on seasonality, ventilation, and the distribution of radon within the cave.

The scientific community accepts the distinctive methodology and measurement techniques used. 

The instrument used and methodology followed are well known to the scientific community in the field of radon measurement.  The levels of radon in the Cango Cave were assessed using Electret Ion Chambers. These chambers were deliberately positioned in the tourist areas of the cave and readings were taken continuously for 24 hours. It was found that there was no noticeable movement of air throughout the cave. The systematic errors were aggregated to calculate a final average error of 6.2% for the radon measurements, indicating a favourable indication of the accuracy of the data. The findings revealed that the Cango Cave, characterized by a single known entrance, has inadequate airflow, particularly in its middle region. When compared to other caves that have radon concentrations >1000 Bq/m3, the Cango Cave is considered to have relatively lower levels. It is a valuable source of data for global research.

The results found are interesting as a database of radiation levels in the caves and for tourists. This manuscript may be accepted as such.

Author Response

[Comment 1] The scientific community accepts the distinctive methodology and measurement techniques used. 

The instrument used and methodology followed are well known to the scientific community in the field of radon measurement.  The levels of radon in the Cango Cave were assessed using Electret Ion Chambers. These chambers were deliberately positioned in the tourist areas of the cave and readings were taken continuously for 24 hours. It was found that there was no noticeable movement of air throughout the cave.

The systematic errors were aggregated to calculate a final average error of 6.2% for the radon measurements, indicating a favourable indication of the accuracy of the data. The findings revealed that the Cango Cave, characterized by a single known entrance, has inadequate airflow, particularly in its middle region. When compared to other caves that have radon concentrations >1000 Bq/m3, the Cango Cave is considered to have relatively lower levels. It is a valuable source of data for global research.

Response 1: Thank you.

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

Minor remarks.
1. Section numeration: 3. Results and discussion and 5. Conclusion.
2. Lines 298-302. And Authors responce: "The results of this study were based
on autumn measurements were not generalized to a full year cycle. 
The conclusion however states that previous summer measurements
compare well with the autumn measurements of this study".
Here It should be noted in text restriction of this analogies.
It is necessary to specify the exact period of the current measurements (the previous work refers to 2004-2005).
And also the fact that the 2004-2005 work used the same methodology
of measurements and devices as the current one.

Author Response

All the amendments were made accordingly.