Characterization and Evaluation of the Efficiency of Organic Amendments and Native Macrophytes for the Treatment of Acid Mine Drainage in Hualgayoc—A Case Study

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

It has been stated a long time ago, that chemical, physical and biological impacts of Acid Mine Drainage (AMD) is a significant environmental problem associated with the mining industry. This is due to its presece in ADM high concentration of heavy metals and acid pH. Therefore, any action taken to reduce AMD,s negative impact on the environment deserves attention. In the article subiect to review, the authors presented the results of research aimed at determining the effect of removing heavy metals present in AMD from Hualgayoc - Peru as a result of the use of Organic Amendments and Native Macrophytes. They stated that combined treatment strategy leveraging biochar, compost and macrophytes might be a cost-effective and sustainable solution to the problem. The reviewer believes that the following comments should be included in the article before its publication in a journal:

1/ Change the title to the new one "Characterization and Evaluation of the Efficiency of Organic Amendments and Native Macrophytes for the Treatment Acid of Mine Drainage- a Case Study"

2/ Change the caption of Fig.2 to the following " Efficiency of heavy metals removal from AMD by different amendment, biochar and microphytes"

3/ Provide the values of the sorption capacity of the tested organic materials in relation to the heavy metals removed expressed e.g. in g/kg org. mat. (dry matter)

4/ Explain how macrophytes and organic amndments containing heavy metals removed from AMD should be handled so that they do not pose a threat to the environment , because the problem is transfered from AMD to the materials mentioned above.

Author Response

Comments 1: 1. It has been stated a long time ago, that chemical, physical and biological impacts of Acid Mine Drainage (AMD) is a significant environmental problem associated with the mining industry. This is due to its presece in ADM high concentration of heavy metals and acid pH. Therefore, any action taken to reduce AMD,s negative impact on the environment deserves attention. In the article subiect to review, the authors presented the results of research aimed at determining the effect of removing heavy metals present in AMD from Hualgayoc - Peru as a result of the use of Organic Amendments and Native Macrophytes. They stated that combined treatment strategy leveraging biochar, compost and macrophytes might be a cost-effective and sustainable solution to the problem. The reviewer believes that the following comments should be included in the article before its publication in a journal: 1/ Change the title to the new one "Characterization and Evaluation of the Efficiency of Organic Amendments and Native Macrophytes for the Treatment Acid of Mine Drainage- a Case Study"   Response 1: The tittle was changed.

Comments 2: 2/ Change the caption of Fig.2 to the following " Efficiency of heavy metals removal from AMD by different amendment, biochar and microphytes"   Response 2: The caption of the picture was changed

Comments 3: 3/ Provide the values of the sorption capacity of the tested organic materials in relation to the heavy metals removed expressed e.g. in g/kg org. mat. (dry matter)   Response 3: It was determined the values of the sorption capacity of the tested organic materials in Table.

Comments 4: 4/ Explain how macrophytes and organic amndments containing heavy metals removed from AMD should be handled so that they do not pose a threat to the environment, because the problem is transfered from AMD to the materials mentioned above. Response 4: It was added in the final part of discussion

Reviewer 2 Report

Comments and Suggestions for Authors

The paper describes the environmental hazards of acid mine drainage (AMD) and the current status of AMD pollution in the Hualgayoc region of Peru, treating AMD with organic amendments, biochar, and native aquatic plants, and analyzing the removal efficiency of heavy metals by microwave plasma-atomic emission spectrometry (MP-AES). The paper's results show significant differences in the removal efficiencies of heavy metals by different treatment methods. The research in this paper is informative for AMD processing. However, there are still some deficiencies in this article, which need to be revised and improved by the authors.

1. The paper demonstrated the removal efficiency of different treatment methods for heavy metals, but did not delve into the removal mechanisms. It is recommended that the operational mechanisms of the different methods be further analyzed to explain the differences in removal efficiency.
2. The paper noted that native plants showed good heavy metal removal in AMD treatments, but did not discuss their long-term remediation capacity. However, long-term exposure to high concentrations of heavy metals and extreme acidic environments can itself have a large impact on the state of the plants, and can it work in the long term?
3. The findings of the paper focus on AMD in the Hualgayoc region of Peru; are these treatments applicable to other regions where there are differences in heavy metal species, concentrations and acidity?
4. The paper mentions the phenomenon that the removal efficiency of heavy metals is enhanced when multiple treatments are used in combination, but the synergistic mechanism has not been explored in depth, and it is recommended that further attempts be made to analyze the mechanism of action.
5. In practical applications, treated AMD may lead to re-release of heavy metals due to changes in environmental conditions (e.g., elevated pH, changes in redox potential). Have relevant experiments been conducted to assess this risk?
6. The heavy metal concentration and acidity of AMD are generally speaking not fixed but vary with time, season and other natural factors, and it is recommended that a long-term control group be set up to verify the dynamic change characteristics of the removal efficiency.
7. The column widths in table 2 are set differently, which affects the look and feel, and it is recommended that similar issues be checked and modified in a uniform manner.

Author Response

Comments 1: The paper describes the environmental hazards of acid mine drainage (AMD) and the current status of AMD pollution in the Hualgayoc region of Peru, treating AMD with organic amendments, biochar, and native aquatic plants, and analyzing the removal efficiency of heavy metals by microwave plasma-atomic emission spectrometry (MP-AES). The paper's results show significant differences in the removal efficiencies of heavy metals by different treatment methods. The research in this paper is informative for AMD processing. However, there are still some deficiencies in this article, which need to be revised and improved by the authors. The paper demonstrated the removal efficiency of different treatment methods for heavy metals, but did not delve into the removal mechanisms. It is recommended that the operational mechanisms of the different methods be further analyzed to explain the differences in removal efficiency. Response 1: Thank you for your valuable feedback. We acknowledge the importance of understanding the removal mechanisms; however, our study primarily focused on evaluating the removal efficiency of different treatment methods rather than analyzing the specific mechanisms involved. While we did not conduct an in-depth investigation of these mechanisms, we have subtly mentioned them throughout the discussion. Future research could explore this aspect in greater detail to complement our findings

Comments 2: The paper noted that native plants showed good heavy metal removal in AMD treatments, but did not discuss their long-term remediation capacity. However, long-term exposure to high concentrations of heavy metals and extreme acidic environments can itself have a large impact on the state of the plants, and can it work in the long term? Response 2: Long-term análisis was explained.

Comments 3: The findings of the paper focus on AMD in the Hualgayoc region of Peru; are these treatments applicable to other regions where there are differences in heavy metal species, concentrations and acidity Response 3: In general, native plants should be chosen and, although they could be replicated based on the extensive scientific literature, the aspect that varies would be the plants native to each region.

Comments 4: The paper mentions the phenomenon that the removal efficiency of heavy metals is enhanced when multiple treatments are used in combination, but the synergistic mechanism has not been explored in depth, and it is recommended that further attempts be made to analyze the mechanism of action. Response 4: The text was changed to be understood more as a recommendation and for future work. Comments 5: In practical applications, treated AMD may lead to re-release of heavy metals due to changes in environmental conditions (e.g., elevated pH, changes in redox potential). Have relevant experiments been conducted to assess this risk? Response 5:  We appreciate this observation. In the present study, no experiments were conducted to assess the potential re-release of heavy metals due to changes in environmental conditions, such as variations in pH or redox potential. However, we acknowledge the importance of this aspect in practical applications. Future studies could address this limitation by conducting long-term tests that simulate dynamic environmental conditions and evaluate the stability of the retained metals in the treated material. Comments 6: The heavy metal concentration and acidity of AMD are generally speaking not fixed but vary with time, season and other natural factors, and it is recommended that a long-term control group be set up to verify the dynamic change characteristics of the removal efficiency. Response 6: It was added as a recommendation. Comments 7: The column widths in table 2 are set differently, which affects the look and feel, and it is recommended that similar issues be checked and modified in a uniform manner. Response 7: During the editing process, it will be reviewed in detail.

Reviewer 3 Report

Comments and Suggestions for Authors

The abstract does not communicate well the main findings of the study. Specific information that could be of interest to the readers should be provided. The main findings with important opinions are acceptable. The authors need to consider these points in the revision stage.

line 131, check the sentence: wich were Carex pichinchensis (CAX). Some typo errors must be polished.
It would be nice to have a schematic diagram of the experiment for easy understanding of the process.
The conclusion needs to be rewritten. Authors should avoid including information corresponding to results or discussion.

Comments on the Quality of English Language

Ther are some typo errors must be polished.

Author Response

Comments 1: The abstract does not communicate well the main findings of the study. Specific information that could be of interest to the readers should be provided. The main findings with important opinions are acceptable. The authors need to consider these points in the revision stage. Response 1: The abstract was changed based in your suggestions.

Comments 2: line 131, check the sentence: wich were Carex pichinchensis (CAX). Some typo errors must be polished Response 2: it was changed based on the suggestion of reviewer.

Comments 3: It would be nice to have a schematic diagram of the experiment for easy understanding of the process. Response 3: It was added a schematic diagram

Comments 4: The conclusion needs to be rewritten. Authors should avoid including information corresponding to results or discussion. Response 4: The conclusions were changed based in your suggestions.

Reviewer 4 Report

Comments and Suggestions for Authors

Dear authors,

I would like to express my gratitude to you for the manuscript.

This study aims to evaluate the effectiveness of organic amendments and native macrophytes in removing heavy metals (As, Cu, Cd, Fe, and Zn) from AMD pollution in the Hualgayoc-Cajamarca area. The authors have comprehensively described the background of the study, the main aim of the research and the gap that this study aims to address, in the introduction. All methods used by the authors have been clearly stated. The results are clearly presented in the relevant section and are accompanied by well-designed tables and diagrams. The authors conducted a fascinating study, collecting important data and interpreting it, as well as comparing the obtained results with current data in the literature. All the authors' conclusions are supported by their findings. There are a few minor grammatical errors and awkward phrasings in the text, but overall it is understandable and conveys its intended meaning.

I have only one recommendation. I would like to suggest that the authors consider including more specific recommendations for future research that could build upon this work in their conclusion.

1) In my view the Figure 1 could be improved. Please remove the scale from the map (1:89,516) and adjust the scale bar accordingly. A single black line representing 10 kilometers should be sufficient. Additionally, the authors can improve the images of macrophyte species by removing letters a, b and c and simply inserting white abbreviations into the photos.

 

Generally, the manuscript in question is a well-designed study that provides a detailed review of the current state of affairs in the field under investigation, as well as clearly articulates the aim of the authors. The main question, originality of the topic, and appropriateness of references do not have any significant drawbacks.

It is possible that the study contains some specific errors in the interpretation of the concentration of the studied chemical elements. Despite the authors' adequate referencing of information that is compared to the findings, it is possible that the authors drew some incorrect conclusions.

In my opinion, this paper could be published with the addition of this information.

Author Response

Comments 1: The abstract does not communicate well the main findings of the study. Specific information that could be of interest to the readers should be provided. The main findings with important opinions are acceptable. The authors need to consider these points in the revision stage. Response 1: The abstract was changed based in your suggestions.

Comments 2: line 131, check the sentence: wich were Carex pichinchensis (CAX). Some typo errors must be polished Response 2: it was changed based on the suggestion of reviewer.

Comments 3: It would be nice to have a schematic diagram of the experiment for easy understanding of the process. Response 3: It was added a schematic diagram

Comments 4: The conclusion needs to be rewritten. Authors should avoid including information corresponding to results or discussion. Response 4: The conclusions were changed based in your suggestions.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors took into accunt the reviewer's comments and made appropriate changes to the content of the article. In the reviewer's opinion, the article can be published in the journal.