Hydrochemical Characteristics and Controlling Factors of the Mingyong River Water of the Meili Snow Mountains, China

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The study presents results of 1 year long sampling campaign of mountain river water providing hydrochemical characteristics of water, providing insights of possible source of water and its applicability of agriculture and drinking purposes. The authors have done quite amount of work of collecting and analyzing data. 

One area were the paper can be improved is strengthening the scientific contribution and implications of this study. 

The authors discuss the source of river water and suggesting rock weathering the results and discussion can be strengthened if sediment data would be present otherwise all the conclusions are made based on the dissolved chemistry data and general knowledge of composition of different minerals. 

Collection and analysis of water from three distinct areas glacier meltwater, midstream and downstream region was not justified as there was lack of discussion/data interpretation on the significance of these three areas. Perhaps the authors can perform isotope analysis to narrow down the potential sources of water: natural vs anthropogenic. 

Formatting and structure:

The references to Figures contains error message which made reading the manuscript and interpreting the results difficult, please fix references to Figures.

Would be good to provide map of the study area and where the three sample areas were, it is not clear in current Figure 1.

Line 61-70 in Introduction some parts of it may be better in Study area. If mentioning residents relying on river water as a justification of the study, it would be good to provide population size.

Lines 76-82 please rephrase

Lines 119-120 please reword

Line 126: what do you mean by "as soon as possible"

Line 127 what do you mean by continuous, please provide in text how often the samples were taken (In Table it is indicated weekly sampling). How did you ensure that samples were collected from relatively same location?

Line 140: what do you mean by "etc." please provide all the chemical species that were analyzed. Why PO4 was not measured along with NO3 and NH4?

Results:

The spatial and temporal sampling was not well explored and justified in the results. Were temporal or spatial changes more significant and affect the applicability of water for agricultural use? Any other implications? 

Did you collect any replicates and had duplicates for laboratory analysis? Could you comment on QA/QC protocol?

Would you like to see more discussion for spatial and temporal variations rather than just presenting the data and describing the Figures.

Pearson Correlation Analysis:

It was not clear how the conclusion about the commonality of sources based on similar R values was done? This section may benefit from more discussion and references to other studies.

I like the Gibbs plot, they very clearly indicate the source ions in river water. Are there studies that would find other sources are important or is it common that weathering of rocks is the main sources of present ions.

Discussion mainly consists of comparing the results of hydrochemical composition from this study to other similar studies, which could be presented earlier in the paper. I would like to see in the discussion section discussion of implications of the findings, the importance of spatial and temporal variations, some discussion of this findings may be important in the context of climate change and anthropocene. 

 

 

 

 

 

Comments on the Quality of English Language

I don't have any concerns with English.

Author Response

Dear Reviewer 1，

We feel great thanks for your professional review work on our article. As you are concerned, there are several problems that need to be addressed. According to your nice suggestions, we have made extensive corrections to our previous draft, and the detailed corrections are listed below. Changes made will be highlighted in the article. And please see the attachment.

Comments 1: One area were the paper can be improved is strengthening the scientific contribution and implications of this study. 

Response 1: We have added some contentsto strengthen the scientific contributions and implications of this study.

Comments 2: The authors discuss the source of river water and suggesting rock weathering the results and discussion can be strengthened if sediment data would be present otherwise all the conclusions are made based on the dissolved chemistry data and general knowledge of composition of different minerals. 

Response 2: We strengthened the discussion and results section using information from sediment studies in the Meili Snow Mountains area by other authors.

Comments 3: Collection and analysis of water from three distinct areas glacier meltwater, midstream and downstream region was not justified as there was lack of discussion/data interpretation on the significance of these three areas. Perhaps the authors can perform isotope analysis to narrow down the potential sources of water: natural vs anthropogenic. 

Responses 3: We added a field investigation basis for selecting three sampling areas to justify the collection and analysis of water from three different areas: glacial meltwater, midstream river and downstream river. as shown below. Based on through investigations and preliminary research findings of the Mingyong River, a comprehensive consideration was given to factors such as surface topography, rock composition, soil characteristics, and distribution of vegetation within the glacier. Subsequently, rational monitoring and sampling points were established in the Mingyong River Basin [21].

Comments 4: The references to Figures contains error message which made reading the manuscript and interpreting the results difficult, please fix references to Figures.

Responses 4: We have revised the reference to the Figures and Tables in the text.

Comments 5: Would be good to provide map of the study area and where the three sample areas were, it is not clear in current Figure 1.

Responses 5: We newly drewFigure 2 to provide a map of the study area and the locations of the three sample areas. as shown below.

Comments 6: Line 61-70 in Introduction some parts of it may be better in Study area. If mentioning residents relying on river water as a justification of the study, it would be good to provide population size.

Response 6: The population size data of the study area is provided to prove that Mingyong river water is the main living and irrigation water for local residents. Part of the statement "The meltwater from the Mingyong Glacier flows into the Mingyong River, which is one of the important tributaries of the Lancang River. More than 300 Local residents rely on the Mingyong River as their primary water source for agricultural irrigation when it converges with the Lancang River" in the introduction has been put into the overview of the study area.

Comments 7: Lines 76-82 please rephrase.

Responses 7: Lines 76-82 were rephrase in our study.

Comments 8: Lines 119-120 please reword.

Responses 8: Lines119-120 were reword in our study.

Comments 9: Line 126: what do you mean by "as soon as possible"

Responses 9: The original statement was not clear, the statement has been modified to "In the field, the gathered samples were placed in a refrigerated container at approximately 4℃to decelerate chemical and physical reactions. Subsequently, they were set to the laboratory for testing".

Comments 10: Line 127 what do you mean by continuous, please provide in text how often the samples were taken (In Table it is indicated weekly sampling). How did you ensure that samples were collected from relatively same location?

Responses 10: The word continuous in line 127 means that during the hydrological year from 7 August 2021 to 7 August 2022, samples will be taken once a week at the scheduled time, except for reasons of heavy snow and avalanches. And we provide the frequency of sampling in the text. We have GPS data for the longitude, latitude, and altitude of each sampling point, and we ensure that the positioning data is calibrated every timewhen we take a sample.

Comments 11: Line 140: what do you mean by "etc." please provide all the chemical species that were analyzed. Why PO4 was not measured along with NO3 and NH4?

Responses 11: The words etc in line 140 are a clerical error by the author, And we have carefully checked the rest of the article to ensure that similar errors do not occur.All the chemicals we analyzed have been listed in the text. The modified statement is: "The key indicators for testing included pH value, electrical conductivity (EC), total dissolved solids (TDS), concentrations of cations (including Na⁺, K⁺, Ca²⁺, Mg²⁺, NH₄⁺) and anions (including Cl^-, NO₃^-, SO₄^2-, F^-) ".

Comments 12: The spatial and temporal sampling was not well explored and justified in the results. Were temporal or spatial changes more significant and affect the applicability of water for agricultural use? Any other implications? 

Responses 12: We have added some contentsto explore the implications of temporal and spatial changes in Mingyong River water chemistry ions. And we added the water quality assessment of glacial meltwater, midstream river water and downstream river water and its applicability to agricultural irrigation.

Comments 13: Did you collect any replicates and had duplicates for laboratory analysis?

Responses 13: Two bottles of the same type of sample were collected, one for the determination of water chemistry and other parameters and one for reserve. And we added that sentence to the text.

Comments 14: Would you like to see more discussion for spatial and temporal variations rather than just presenting the data and describing the Figures.

Responses 14: We addedsome contents to discuss the spatial and temporal changes of the hydrochemical characteristics of Mingyong River to enrich the content of the paper.

Comments 15: It was not clear how the conclusion about the commonality of sources based on similar R values was done? This section may benefit from more discussion and references to other studies.

Responses 15: The conclusion about the commonality of sources based on similar R values, We found the following published literature in which this representation can be found. For example, Wu, J., Li, P., Qian H. et al. Using correlation and multivariate statistical analysis to identify hydrogeochemical processes affecting the major ion chemistry of waters: a case study in Laoheba phosphorite mine in Sichuan, China[J]. Arabian Journal of Geosciences, 2014, 7: 3973-3982. https://doi.org/10.1007/s12517-013-105 7-4and Li, P., Qian, H., Wu, J. et al. Major ion chemistry of shallow groundwater in the Dongsheng Coalfield, Ordos Basin, China[J]. Mine Water and the Environment, 2013, 32(3): 195-206. http://dx.doi.org/10.1007/s10230-013-0234-8

Comments 16: I like the Gibbs plot, they very clearly indicate the source ions in river water. Are there studies that would find other sources are important or is it common that weathering of rocks is the main sources of present ions.

Responses 16: According to the results of this study, rock weathering is the main source of ions in Mingyong River.

Comments 17: Discussion mainly consists of comparing the results of hydrochemical composition from this study to other similar studies, which could be presented earlier in the paper. I would like to see in the discussion section discussion of implications of the findings, the importance of spatial and temporal variations, some discussion of this findings may be important in the context of climate change and anthropocene. 

Responses 17: We adjusted the structure of the paper, moving the content comparing the hydrochemical characteristics and controlling factors of the water body in this study with the results of other similar studies to the frontof the article. In the discussion part, we mainly discussed the significance of the research results of this paper, discussed the impact of human activities on the chemical characteristics and water quality of river water, and suggested that in order to make better use of water resources, reasonable water resources protection measures should be put into practice.

We really appreciate the comments on this article. Because of your effective suggestions, our article has been greatly improved and progressed.

Best regards

All authors

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript entitled “Hydrochemical Characteristics and Controlling Factors of the Mingyong River Water of the Meili Snow Mountains, China” provides some good results. Therefore, the current manuscript could be accepted for publication, but after going through a minor revision.      

1.     Keywords should be more eye-catching.

2.     “Error! Reference source not found” this error is spread throughout the manuscript.

3.     “how does the variation characteristics of cation and ions in the natural water body of Mingyong River in Meili Snow Mountains?” it should be cations and anions.

4.     “However, the variations in other ions are influenced by complex factors, resulting in differences in their changes.” Some of these complex factors should be mentioned.

5.     The pH trend should be more clarified.

6.     Some examples of the recent articles that could be useful for enriching the manuscript are:

https://doi.org/10.1016/j.agwat.2020.106167

https://doi.org/10.1016/B978-0-323-85581-5.00023-9

7.      English language should be improved.

 

Comments on the Quality of English Language

English language should be improved.

Author Response

Dear Reviewer 2，

We appreciate your comments and suggestions. These suggestions are very helpful for our article. And we will make some modifications according to the requirements. Changes made will be highlighted in the article. And please the attachment.

Comments 1: Keywords should be more eye-catching.

Responses1 : We changed the contentsof the keywords to make them more eye-catching. as shown below. 

Keywords: Meili Snow Mountains; Mingyong River; hydrochemical characteristics; controlling factors; water quality

Comments 2: “Error! Reference source not found” this error is spread throughout the manuscript.

Responses 2: We have revised the reference to the Figures and Tables in the text.

Comments 3: “how does the variation characteristics of cation and ions in the natural water body of Mingyong River in Meili Snow Mountains?” it should be cations and anions.

Responses: We sincerely thank the reviewer for careful reading. As suggested by the reviewer, we have corrected the“cation and ions”into“cations and anions”.

Comments 4: “However, the variations in other ions are influenced by complex factors, resulting in differences in their changes.” Some of these complex factors should be mentioned.

Responses 4: We incorporate various complex factors that influence the variation characteristics of other ions to explain the differences in ion changes.as shown below. 

Meanwhile, the concentrations of other ions gradually increase. However, the variations in other ions are influenced by complex factors, resulting in differences in their changes. With the accumulation of leaching and evaporation, the concentrations of Cl^-, Na⁺, K⁺, and Mg²⁺ in the water will increase with rising salinity. However, the ratio of these cations to each other gradually decreases because Na⁺ is easily leached and affected by the exchange of adsorbed cations, such as Ca²⁺ replacing Na⁺ on colloids. In contrast, the migration capacity of K⁺ is much lower than that of Na⁺ since K⁺ is easily absorbed by plants or adsorbed by soil. Consequently, the proportions of Cl^-, Na⁺, K⁺, and Mg²⁺ in river water gradually decrease as the content and proportion of SO₄^2- increase. NO₃^- in the groundwater of the Mingyong River Basin originates from the decomposition and nitrification of animal and plant carcasses and excreta by microorganisms. This process directly produces NO₃^- or initially forms NO₂^-, which is then oxidized to NO₃^-. This NO₃^- subsequently enters the river water through lateral recharge and exchange with shallow groundwater, thereby increasing the NO₃^- content in the river. However, due to the small population in the Mingyong River Basin, the increase in NO₃^- content in the river water is relatively slow [26].

Comments 5: The pH trend should be more clarified.

Responses 5: We added the reasons for the pH change to make the trend of pH change more clarified.as shown below.

The pH value reflects the activity of H⁺ in the river. During the gradual decrease in the water level of the Mingyong River from January to June, the pH value generally decreased, showing an opposite trend to the changes in ion concentrations. This indicates that ions increased the activity of H⁺ when dissolved in the water, suggesting that the presence of these ions is primarily due to the input of more acidic substances [33].

Comments 6: Some examples of the recent articles that could be useful for enriching the manuscript are:

https://doi.org/10.1016/j.agwat.2020.106167

https://doi.org/10.1016/B978-0-323-85581-5.00023-9 

Responses 6: We sincerely appreciate the valuable comments. We have checked the literature carefully and added more useful references in the revised manuscript.

Comments 7: English language should be improved.

Responses 7: Thanks for your suggestion. We do invite a native expert colleague has verified and refined the scientific language. And we hope the revised manuscript could be acceptable for you.

We really appreciate the comments on this article. Because of your effective suggestions, our article has been greatly improved and progressed.

Best regards

All authors

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

It should be a comparison of the differences in the same chemical property in different locations, rather than a comparison between different chemical properties.

Abstract is too long!

Has time variation been studied?

The introduction lacks relevant research progresses. Where is the innovations for your study?

The first letter of the first row/column of the tables should be capitalized.

The structure of the paper needs to be greatly revised! Follow the writing conventions: Results -  Discussion - Conclusion. Write only one paragraph of the conclusion.

Based on the above, this paper needs to be rewritten!

L431,441,444....:TH (Error! Reference source not found.) ?

Comments on the Quality of English Language

Moderate editing of English language required. 

Author Response

Dear Reviewer 3，

We feel great thanks for your professional review work on our article. As you are concerned, there are several problems that need to be addressed. According to your nice suggestions, we have made extensive corrections to our previous draft, the detailed corrections are listed below. Changes made will be highlighted in the article. Please see the attachment.

Comments 1: It should be a comparison of the differences in the same chemical property in different locations, rather than a comparison between different chemical properties.

Responses 1: We added a comparison of the differences of the same chemical in different locations and explained the reasons for the differences.You can see our modifications in section 3.1.1. The Spatial Variation Characteristics of Hydrochemistry in River Water.

Comments 2: Abstract is too long!

Responses 2: We simplified the contentsof the as shown below. 

Abstract: The hydrochemical characteristics of rivers are affected by many natural factors such as the nature of watershed bedrock, watershed environment, vegetation and human activities. Examining the hydrochemistry of a river can provide insights about the baseline hydrological conditions, the geochemical environment, and the overall water quality of the river. In order to examine the hydrochemical characteristics and controlling factors of the water in the Mingyong River, a total of 154 water samples were gathered from the glacier meltwater, midstream, and downstream regions. The findings revealed that the dominant cations are Ca²⁺ and Mg²⁺, while the dominant anions are HCO₃^- and SO₄^2-. The mass concentration order of cations is Ca²⁺ > Mg²⁺ > Na⁺ > K⁺, and for anions, it is HCO₃^- > SO₄^2- > NO₃^- > Cl^-. The average concentration of TDS in the river water is 81.69 mg·L^-1, with an average EC of 163.63 μs·cm^-1 and an average pH of 8.99. Temporal variations in ion concentrations exhibit significant disparities between the glacier melting and accumulation periods. High ion concentration values are primarily observed during the glacier accumulation period, while values decrease during the glacier melting period due to increase precipitation. The river water in the study region is categorized as (HCO₃^-+SO₄^2-) -(Ca²⁺+Mg²⁺) type. In addition, Pearson correlation analysis indicates clear relationships between different parameters, indicating that the major ions were mostly influenced by materials from the Earth's crust. The primary principal source of solutes in the water of the Mingyong River is rock weathering. The cations and anions present in the river water are derived from the breakdown of carbonate rocks and the dissolving of substances from silicate rocks. However, the influence of carbonate rocks is more significant compare to that of silicate rocks. The Mingyong River water is suitable for agricultural irrigation with minimal land salinization damage, making it appropriate for agricultural purposes but not suitable for people and animals to drink directly.

Comments 3: Has time variation been studied?

Responses 3: We studied the timevariation characteristics of Mingyong River water in section 3.1.2 The Temporal Variation Characteristics of Hydrochemistry in River Water.

Comments 4: The introduction lacks relevant research progresses. Where is the innovations for your study?

Responses 4: We included relevant research progresses in the introduction. The innovations of this study lies in the fact that the predecessors conducted a short-term (less than one week) study on the water chemistry of Mingyong Glacier Basin in Meili Snow Mountains in the 1980s, while our study is a relevant study on the characteristics of long-term water hydrochemical characteristics, controlling factors and water quality in this study area. The hydrochemical characteristics and controlling factors of Mingyong River water were analyzed, the source of solute in the river water was explained, and the water quality of the river water was evaluated to verify whether it was suitable for agricultural irrigation and drinking for human and livestock.

Comments 5: The first letter of the first row/column of the tables should be capitalized.

Responses 5: We capitalized the first letter of the first row/column of all the tables in the text.

Comments 6: The structure of the paper needs to be greatly revised! Follow the writing conventions: Results -  Discussion - Conclusion. Write only one paragraph of the conclusion. Based on the above, this paper needs to be rewritten!

Responses 6: We have revised the structure of the article following the Result- Discussion- Conclusion writing convention and write only one paragraph of the conclusion. And rewrote this paper.

Comments 7: L431,441,444....:TH (Error! Reference source not found.) ?

Responses 7：We have revised the reference to the Figures and Tables in the text.

Comments 8: Moderate editing of English language required. 

Responses 8: Thanks for your suggestion. We do invite a native expert colleague has verified and refined the scientific language. And we hope the revised manuscript could be acceptable for you.

We really appreciate the comments on this article. Because of your effective suggestions, our article has been greatly improved and progressed.

Best regards

All authors

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

The discussion content is too limited. Some of the text in the results section can be included in the discussion part. 

Most of the figures are not clear. Please modify. 

Author Response

Reply to reviewer,

 

We appreciate your comments and suggestions. These suggestions are very helpful for our article. And we will make some modifications according to the requirements. Changes made will be highlighted in the article.

1. We added some of the results to the discussion to enrich the discussion section. As shown below

4. Discussion

River is an important part of surface water and an important link of water cycle between land and sea, and its hydrochemical characteristics are important parameters to assessment water quality. Rivers constantly scour, erode and dissolve rocks in the process of flow, and are affected by climate, soil, animals and plants, as well as human activities. The hydrochemical characteristics of rivers can indicate the hydrochemical environment of their region, explain the chemical processes of rivers, and reflect the sources of dissolved substances in the river [55,56]. The variations in the dominant ions composition of the water chemistry within the basin serve as a primary indicator for investigating the process of chemical weathering, thereby enabling an examination of its origins, rate of weathering, and impact on climate dynamics [57,58]. TDS represents the comprehensive characteristics of solute quality in water and has certain representative value [59]. According to our study, the water samples in the sampling area are primarily of the (HCO₃^- +SO₄^2-)-(Ca²⁺ +Mg²⁺) type, this result is consistent with the results obtained by others in this study area. The dominant cations in the river water of Mingyong River Basin are Ca²⁺ and Mg²⁺, and the dominant anions are SO₄^2- and HCO₃^-, and the weathering of rocks dominated by carbonate rocks and silicic rocks is the main source of solute and with only minor effects from anthropogenic activities in this basin. The source of solute in the river water is also fully verified by the limestone, siliceous rocks and calc sandstone rich in the river basin [15,19-20]. When the river water passes through evaporite rock areas, substantial amounts of Ca²⁺ and SO₄^2- enter the river through leaching and oxidation processes, and SO₄^2- replaces HCO₃^- as the predominant anion in the midstream and downstream river water. When the ions dissolved in the water, they increased the activity of H⁺, causing the pH value to generally decrease [33]. This decrease in pH exhibited an opposite trend to the changes in ion concentrations. The hydrochemical characteristics and controlling factors of Mingyong River water are similar to those of the Baishui Glacier No.1 in the Yulong Snow Mountains and the Hailuogou Glacier in the Gongga Mountains. The SAR, %Na, and TH indices in the glacier meltwater, midstream and downstream river water of the Mingyong River all fall within the safe range designated for irrigation water, but not suitable for people and animals to drink directly. This study area is a famous tourist attraction in China, and a large number of tourist activities may affect the hydrochemical characteristics and water quality of the river. In order to make better use of water resources, reasonable water resources protection measures should be put into practice.

2. We modified all the figures in the full text to make them clearer, and organized the original figures files in the attachment and uploaded them. And we hope the revised manuscript could be acceptable for you.

 

We really appreciate the comments on this article. Because of your effective suggestions, our article has been greatly improved and progressed.

 

Best regards

All authors

Round 3

Reviewer 3 Report

Comments and Suggestions for Authors

I am okay with the revision.