A Review of Heavy Metal Migration and Its Influencing Factors in Karst Groundwater, Northern and Southern China
Round 1
Reviewer 1 Report (New Reviewer)
Manuscript ID: Water-2645208
General comments:
In the review entitled "A review of on the migration of heavy metals in the karst groundwater", authors have the focused on the migration characteristics of heavy metals of karst groundwater in southern and northern China and highlighted the effect of different environmental contexts such as atmospheric (precipitation), vegetation, soil, rock and aquifer on the behaviour of heavy metals. This work seems to be adequate to be published after major revisions. The following issues should be addressed:
Ø Revise the title of the review article by making it more relevant and attractive.
Ø Explain the novelty of the current work and how the current review is unique from the previous. Discuss it in the introduction.
Ø The introduction is too short and must be enriched by citing recent works.
Ø Add a geological map indicating southern and northern China karst areas.
Ø Add a column containing the allowed limit of the heavy metals in the ground limit with data provided in Table 2.
Ø Improve the quality of Figures. The current quality is inferior.
Ø Add at least 3 more relevant figures
Ø In Table 7, the presented data have single supporting references; it should have more supporting studies and references.
Ø The conclusion is short; it should be revised to summarize more important review findings.
Ø In conclusion, the authors should add the specific scientific contribution of the current review.
Ø Add more future prospects
Ø Overall, adding some illustrative figures can make the review more attractive.
Ø Special attention is required to check the language and formatting; some parts are like copy-paste.
Ø References are outdated. Try to add maximum updated works (2019-----onward).
Comments for author File: 
Comments.pdf
Minor editing
Author Response
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Author Response File: 
Author Response.docx
Reviewer 2 Report (New Reviewer)
This review provides an overview of heavy metal migration in karst groundwater. This review is well-established and can be recommended for publication with minor revisions.
1. What are the key factors that make karst groundwater vulnerable to pollution, and why is post-pollution treatment challenging in karst environments?
2. How important are karst groundwater resources for social and economic development in China's karst areas, and why is their protection crucial?
3. How do heavy metals enter groundwater in karst regions, and what potential risks do they pose to human health and the food chain?
4. What are the main characteristics of heavy metal migration in karst groundwater in southern China, and how do they differ from those in northern China?
5. Can you provide an overview of the research methods used to study heavy metal migration in karst groundwater in both southern and northern China?
6. What are the primary focus areas in the research on heavy metal migration in karst groundwater in southern China, and what models are commonly used to study this phenomenon in the region?
7. In northern China, what are the dominant characteristics of heavy metal migration in karst groundwater, and what models are typically employed for research?
8. How can the coupling of surface water and groundwater at the karst basin scale be better addressed in the study of heavy metal migration in southern China?
9. What specific challenges or areas of exploration should be prioritized in the study of heavy metal migration in karst groundwater in northern China?
10. How does the research on heavy metal migration in karst groundwater in China contribute to our understanding of pollution prevention and control in these environments, and what are the potential future research directions in this field?
Author Response
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Author Response File: Author Response.docx
Round 2
Reviewer 1 Report (New Reviewer)
It can be accepted now
This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.
Round 1
Reviewer 1 Report
The current article entitled “A review of heavy metal migration in groundwater in karst areas of China’’ is interesting and needed nowadays. I suggest minor revisions needed to be done.
1. There are some typographical mistakes throughout the manuscript.
2. Add some more sources of heavy metals contamination in the introduction section.
3. Make the discussion portion more precise in the light of mentioned observations.
4. Cross-check the citations in the text with the reference portion.
It needs language improvement thoroughly
Author Response
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Author Response File: Author Response.docx
Reviewer 2 Report
In this paper, the authors reviewed the previous researches related the heavy metal migration in karst groundwater at the north and the south China. The comparison of heavy metal migration in two area and the mechanisms of groundwater flow and of the solute transports were main in this manuscript. The major drawback of this paper is lack of the quantitative or numerical description and data in the material. I have a few comments as follows for the publication:
Need to increase the academic and the review originality of this paper
1. To be published in ‘Water’, should not focus on an application to any specific area, but rather to the general heavy metal migration processes in karst groundwater. It is not clear what scientific or academic information author(s) are suggesting for the readers. Even this is the review type of previous studies related to the heavy metal migration in karst areas of China, the major drawback of this paper is its lack of quantitative description or data in the manuscript. As the review paper, author(s) should support the meaningful results about the topic more numerically or briefly. For example, a large portion of Section 2 (p3 – p8) consist of only common materials that everybody agreed with. “Migration depends on various karst structures rather than typical aquifer.” As a review paper, author(s) should support more quantitative comparison between the south and the north karst in China. (Examples: fracture or pipeline distribution difference, average pore size (porosity) difference of the main bed rock forming the karst area, major heavy metals and their concentrations in two karst groundwaters. Also, the geology (quantitative data and the component comparison of the karst formation as parent rock properties) and the differences of soil or the vegetation distribution, etc.)
2. The section 3 (p8 – 13) is the same. The author(s) add the more information such as average groundwater flow velocity range of two areas and the comparison of annual precipitation, recharge rate and run-off (leakage) ratio, etc. because the author(s) described that the difference groundwater pattern and the heavy metal migration mechanisms are dependent them. There exist the differences of major heavy metal pollution between the North and the South karst area? Also, concentration differences in two groundwater from the bed-rock, soil origins? How about the comparison of vegetation covered area or type of major plants or any biological parameters affecting the migration at two karst area?
3. At the section 4 for the numerical simulation part, as the review for the groundwater flow modeling in karst area, parameter values like model scale (grid number, and model domain like aquifer properties representing karsts), input parameters applied to rather than the general description of modeling process. Also, how to apply these modeling to the south or the north of karst area in China? Are there any limitations or considerable factors to apply these codes to two karst area? Which code is more available for?
4. The volume of the paper is too big and it was mostly composed of general description (materials accepted by everybody) and it is hard to find out the academical originality to support readers. The comparison of heavy metal migrations in karst groundwater at two distinct area in China should be more quantitatively added for the publication.
2. Many problems in English and compilation (Examples shown below)
1. Missing Figure 2 in the manuscript (see the line 117 on page 4).
2. Line 17 on page 1 ( re-search)
3. Line 72 on page 2 (connect lines)
4. Line 187 on page 6 (semper? – temper)
5. Line 268 on page 8 (so t transport)
6. In Table 1, ‘distribution’ to ‘Distribution’; goundwa-ter; ( limestone )- remove the space, etc.
There are many order typos in manuscripts.
The reviewer strongly recommends that author(s) request the native to review the manuscript in English before presentation!
Author Response
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Author Response File: Author Response.docx
Reviewer 3 Report
· Line 21-23 is repetition, it should be avoided
· Abstract lacks proper structuring. The study rationale should be followed by Methodology and then results. Line 24-25 should be part of the methodology. It should not be mixed. Even results are not very meaningful and not enough results regarding migration in karst. The abstract should be rewritten with a clear methodology and results. It should be concise
· Since this is a review, the introduction seems in a style of a research article, in fact introduction of a review should be different. Content of the introduction should be based on the study’s objectives, currently its not supporting
· The caption of Figure 1 is still not complete
· Where is Figure 2, it’s not in the manuscript.
· In Table 1, also mention the city or area where specific karst is distributed
· The quality of Figure 3 is low, it should be improved
· Not enough literature is provided in a simulation experiment
· Table 2 could be shifted to supplementary information
· this review can be improved by introducing some research results and illustrations in the form of figures. Currently, it only has text writing which is not supported by specific results which makes it boring to read. Currently, it only has a few crossectional diagrams which is not enough to support this review. Furthermore, what are the findings of the author from this review that should also be illustrated by supported figures and sketches.
· This review should also mention what are the challenges to the karst system, and how it can be overcome with future prospects as well.
This article can be made more concise and meaningful. There are repetitions in some sections which could be corrected.
Author Response
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Author Response File: Author Response.docx
Round 2
Reviewer 3 Report
· Line 21-23 is repetition, it should be avoided
· Abstract lacks proper structuring. The study rationale should be followed by Methodology and then results. Line 24-25 should be part of the methodology. It should not be mixed. Even results are not very meaningful and not enough results regarding migration in karst. The abstract should be rewritten with a clear methodology and results. It should be concise
· Since this is a review, the introduction seems in a style of a research article, in fact the introduction of a review should be different. The content of the introduction should be based on the study’s objectives, currently it’s not supporting
· The caption of Figure 1 is still not complete and quality should be improved.
· Where is Figure 2, it’s not in the manuscript.
· In Table 1, also mention the city or area where specific karst is distributed
· The quality of Figure 3 is low, it should be improved
· Not enough literature is provided in a simulation experiment
· Table 2 could be shifted to supplementary information
· This review can be improved by introducing some research results and illustrations in the form of figures. Currently, it only has text writing which is not supported by specific results which makes it boring to read. Currently, it only has a few cross-sectional diagrams which is not enough to support this review. Furthermore, what are the findings of the author from this review that should also be illustrated by supported figures and sketches.
· This review should also mention what are the challenges to the karst system, and how it can be overcome with future prospects as well.
Review paper requires much more careful attention to the quality of text, sentence structure and grammar
Author Response
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Author Response File: Author Response.docx
