Assessment of Multi-Depth Water Quality Dynamics in an Artificial Lake: A Case Study of the Ribnica Reservoir in Serbia

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Peer Review Report: Assessment of Multi-depth Water Quality Dynamics in an Artificial Lake: A Case Study of the Ribnica Reservoir in Serbia

 

General Comments

The manuscript presents a comprehensive study of water quality dynamics in the Ribnica Reservoir, Serbia, using the Serbian Water Quality Index (SWQI) and the Canadian Water Quality Index (CWQI). The study is timely, given the ecological and socio-economic importance of the reservoir, and contributes to the limited literature on this specific water body. However, the manuscript has several areas that require improvement, including incomplete data reporting, methodological clarifications, and a more robust discussion of results.

 

Major Concerns

Incomplete Data Reporting:

The manuscript notes the absence of Total Coliform data, a critical parameter for SWQI calculations and public health assessments. This gap significantly undermines the comprehensiveness of the water quality assessment, particularly for a drinking water reservoir. The authors should justify why this data was unavailable and discuss how its absence impacts the reliability of the SWQI results.

 

Several parameters (e.g., BOD, suspended solids, heavy metals) have missing data at certain depths. The manuscript does not adequately explain why these measurements were not conducted consistently across all depths and profiles, which weakens the multi-depth analysis.

 

 

Methodological Clarifications Needed:

The sampling frequency is inconsistent (two samplings in 2021 vs. one in 2022). The authors should clarify why only one sampling was conducted in 2022 and discuss how this affects the comparability of results between years.

 

The manuscript does not specify how weights (w_i) for SWQI parameters were determined. This information is critical for understanding the index's sensitivity to different parameters.

 

 

Limited Discussion of Heavy Metal Sources:

The study identifies elevated concentrations of aluminum (Al), mercury (Hg), chromium (Cr), and copper (Cu) as key concerns for aquatic life. While natural (e.g., lithological) and anthropogenic (e.g., water treatment) sources are briefly mentioned, the discussion lacks depth. The authors should elaborate on potential sources, such as specific industrial or agricultural activities in the Zlatibor region, and quantify their contributions if possible.

 

 

Inconsistent Terminology and Errors:

 

The term "highest n se" is used repeatedly in the CWQI results section without explanation.

 

The manuscript contains minor typographical errors, such as "1000 cm and 1200 cm" instead of meters (10 m and 12 m).

 

The term "Electroconductivity" should be standardized to "Electrical Conductivity" to align with common scientific terminology.

 

 

Limited Temporal and Spatial Analysis:

The study covers only two years (2021-2022) with limited sampling events, which restricts the ability to assess long-term trends or seasonal variations. The authors should acknowledge this limitation and discuss how it impacts the generalizability of their findings.

 

 

Recommendation

Major Revision

The manuscript has significant potential to contribute to the literature on reservoir water quality management, particularly in the context of protected areas. However, the identified issues—data gaps, methodological ambiguities, and limited discussion of heavy metal sources—require substantial revisions to ensure scientific rigor and clarity. Addressing these concerns will strengthen the manuscript’s contribution to sustainable water resource management and its relevance to both regional and international audiences.

Comments for author File: Comments.pdf

Author Response

General Comments

The manuscript presents a comprehensive study of water quality dynamics in the Ribnica Reservoir, Serbia, using the Serbian Water Quality Index (SWQI) and the Canadian Water Quality Index (CWQI). The study is timely, given the ecological and socio-economic importance of the reservoir, and contributes to the limited literature on this specific water body. However, the manuscript has several areas that require improvement, including incomplete data reporting, methodological clarifications, and a more robust discussion of results.

Major Concerns

Incomplete Data Reporting:

The manuscript notes the absence of Total Coliform data, a critical parameter for SWQI calculations and public health assessments. This gap significantly undermines the comprehensiveness of the water quality assessment, particularly for a drinking water reservoir. The authors should justify why this data was unavailable and discuss how its absence impacts the reliability of the SWQI results.

Several parameters (e.g., BOD, suspended solids, heavy metals) have missing data at certain depths. The manuscript does not adequately explain why these measurements were not conducted consistently across all depths and profiles, which weakens the multi-depth analysis.

We appreciate your observation and fully acknowledge the importance of comprehensive monitoring, particularly for a reservoir used for drinking water supply and located within a protected area. The data utilized in this study were obtained from official annual reports published by the Serbian Environmental Protection Agency, (authorized institution for water quality monitoring in Serbia) which defines the scope of monitoring and the parameters assessed each year. It is important to note that the Serbian Environmental Protection Agency does not apply a uniform set of parameters across all reservoirs—selection varies based on methodological and institutional decisions.

However, we agree that the omission of Total Coliforms, as well as certain heavy metals, from the official monitoring of the Ribnica Reservoir is not an appropriate decision, given its role in water supply and ecological conservation. In the manuscript, we repeatedly highlighted the limitations of existing monitoring practices, emphasizing that the absence of key microbiological and chemical data presents a methodological gap and complicates an accurate water quality assessment.

While the authors had no influence over the selection of monitored parameters, the findings of this study underscore the need for a more systematic and comprehensive monitoring approach, including the introduction of continuous microbiological assessments and broader chemical contaminant analysis. We hope that our results will contribute to future initiatives aimed at improving monitoring practices and ensuring the long-term protection of water quality in the Ribnica Reservoir.

Methodological Clarifications Needed:

The sampling frequency is inconsistent (two samplings in 2021 vs. one in 2022). The authors should clarify why only one sampling was conducted in 2022 and discuss how this affects the comparability of results between years.

We acknowledge the reviewer’s concern regarding the inconsistency in sampling frequency between 2021 and 2022. The dataset used in our study reflects the sampling dynamics established that year, with two sampling campaigns conducted in 2021 and only one in 2022. Since we did not perform the sampling ourselves but relied on the available official data from annual reports of Serbian Environmental Protection Agency, our analysis was necessarily constrained by this variation.

To ensure comparability, we calculated annual average values for 2021 based on two measurements, while 2022 assessments rely on a single data point. We recognize that this discrepancy limits direct statistical comparisons between years; however, it still provides valuable insights into water quality trends and key variations. Additionally, throughout the manuscript, we emphasized that irregular monitoring frequencies can pose a challenge for long-term assessments, particularly in water bodies designated for drinking water supply and located within protected areas.

The manuscript does not specify how weights (w_i) for SWQI parameters were determined. This information is critical for understanding the index's sensitivity to different parameters.

Thank you for your observation. To enhance clarity and transparency in the methodological framework of this study, we will include a detailed table (Table 3) outlining the weighting criteria applied in the Serbian Water Quality Index (SWQI) calculations. This table, originally presented in a previous publication https://doi.org/10.3390/su17094074, provides a systematic classification of water quality parameters according to their respective weight units (wᵢ), which directly influence the final SWQI score.

SWQI is developed by the Serbian Environmental Protection Agency (SEPA) on the basis of WQI, originally developed by Scottish Development Department in 1976 and incorporates ten key water quality parameters: Temperature (T), pH, Electrical Conductivity (EC), Oxygen Saturation (OS), Biochemical Oxygen Demand (BOD), Ammonium (NH₄⁺), Total Nitrogen (TN), Suspended Solids (SS), Orthophosphate (PO₄³⁻), and Total Coliforms (TC). The index is calculated using the following equation:

SWQI = ,

where qᵢ represents the water quality of the i-th parameter, and wᵢ is the assigned weight unit for that parameter, indicating its relative importance in the overall assessment.

The weighting scheme reflects established environmental standards and expert evaluations of parameter significance in water quality dynamics. Oxygen saturation, biochemical oxygen demand, and microbial contamination indicators (Total Coliforms) generally carry higher weighting due to their direct implications for water usability and ecological health. Temperature, pH, and electrical conductivity are assigned lower weights because, although they influence water quality, their variations are largely governed by natural processes within aquatic systems.

We acknowledge the importance of transparency regarding index sensitivity and have incorporated this structured classification within the revised manuscript under the title "Weighting Criteria for SWQI Parameter Assessment", ensuring a comprehensive methodological explanation.

Limited Discussion of Heavy Metal Sources:

The study identifies elevated concentrations of aluminum (Al), mercury (Hg), chromium (Cr), and copper (Cu) as key concerns for aquatic life. While natural (e.g., lithological) and anthropogenic (e.g., water treatment) sources are briefly mentioned, the discussion lacks depth. The authors should elaborate on potential sources, such as specific industrial or agricultural activities in the Zlatibor region, and quantify their contributions if possible.

In our study, we identified elevated concentrations of aluminum (Al), mercury (Hg), chromium (Cr), and copper (Cu) as key concerns for aquatic life in Ribnica Reservoir. While we previously noted that both natural (lithological) and anthropogenic (water treatment) factors contribute to their presence, we recognize the need for a more detailed discussion of specific sources.

The geological structure of the Zlatibor region plays a significant role in heavy metal concentrations in water bodies, as the surrounding ultramafic formations contain Al-Cr spinel and iron oxide minerals. Previous studies have confirmed interactions between these lithological units and surface and groundwater, contributing to natural metal leaching into the reservoir. Additionally, sediment analysis has indicated increased levels of Ni, Cr, Zn, Cd, and Hg, further supporting the influence of geochemical processes in metal transport.

Regarding anthropogenic sources, aluminum sulfate is commonly used in water treatment processes, which can lead to residual Al levels in aquatic systems. Zlatibor is recognized touristic destination in Serbia and does not have active large-scale industrial operations. However, tourism-related infrastructure development and increased urbanization—especially in the Čajetina and Zlatibor areas—have intensified construction activities and wastewater discharge, which could be contributing to heavy metal inputs. Additionally, while agriculture is not a dominant land use in this region, localized farming activities, including pesticide and fertilizer application, could introduce trace amounts of metals into the watershed.

Although our study did not directly quantify the contribution of each source, the combination of lithological characteristics, water treatment processes, and expanding urbanization suggests a multifactorial influence on heavy metal concentrations. Future research with targeted geochemical tracing and sediment core analysis would help provide a more precise attribution of these sources. We have incorporated an expanded discussion on these factors in the revised manuscript to address this limitation.

Inconsistent Terminology and Errors:

The term "highest nse" is used repeatedly in the CWQI results section without explanation.

The manuscript contains minor typographical errors, such as "1000 cm and 1200 cm" instead of meters (10 m and 12 m).

The term "Electroconductivity" should be standardized to "Electrical Conductivity" to align with common scientific terminology.

We appreciate the reviewer’s attention to consistency and terminology. The term nse is abbreviation for normalized sum of excursions. The definition of this term is added in section Materials and Methods.

Regarding the notation for depth measurements, we have deliberately retained centimeter (cm) units rather than converting to meters, as this aligns with the official reporting format used in the Serbian Environmental Protection Agency’s annual water quality reports, as well as our previously published research. Maintaining this convention ensures consistency with national monitoring practices and facilitates direct comparison with official datasets.

Regarding the term "Electroconductivity," we recognize that "Electrical Conductivity" is the more commonly used term in scientific literature. To ensure uniformity, we standardized this terminology across the manuscript, using "Electrical Conductivity" throughout. 

Limited Temporal and Spatial Analysis:

The study covers only two years (2021-2022) with limited sampling events, which restricts the ability to assess long-term trends or seasonal variations. The authors should acknowledge this limitation and discuss how it impacts the generalizability of their findings.

We recognize that this research is based on a limited dataset collected over a two-year period (2021–2022), with a relatively small number of sampling occasions. Such a temporal limitation constrains the ability to thoroughly assess long-term trends and seasonal variability in water quality dynamics. Although the data offer meaningful insights into vertical water quality distribution and allow for methodological evaluation, they may not fully represent year-to-year fluctuations or the influence of broader climatic and hydrological factors.

To address this constraint, we have interpreted our results with caution, situating them within the bounds of the existing data while underscoring the importance of more comprehensive and regular monitoring. We highlight that future research involving more frequent sampling across extended timeframes would greatly enhance the reliability of temporal analyses and improve the applicability of findings, especially in reservoirs exposed to both hydrological changes and human activity.

In addition, we intend to continue following official reports and datasets released by competent institutions. Should further data become accessible, they will be incorporated into subsequent investigations to support more robust long-term evaluations. We also recommend the adoption of standardized, high-frequency monitoring systems to ensure more effective water quality management, particularly in reservoirs designated for drinking water supply within ecologically sensitive zones.

Recommendation

Major Revision

The manuscript has significant potential to contribute to the literature on reservoir water quality management, particularly in the context of protected areas. However, the identified issues—data gaps, methodological ambiguities, and limited discussion of heavy metal sources—require substantial revisions to ensure scientific rigor and clarity. Addressing these concerns will strengthen the manuscript’s contribution to sustainable water resource management and its relevance to both regional and international audiences.

Thank you for the reviewer’s helpful comments. By making the recommended changes, we explained key points more clearly and present our results more accurately. Your suggestions greatly improved the clarity and overall quality of our work.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

This manuscript presents a thorough and well-structured assessment of multi-depth water quality dynamics in the Ribnica Reservoir, using both the Serbian Water Quality Index (SWQI) and the Canadian Water Quality Index (CWQI). The dual-index approach is commendable, offering both localized and internationally comparable insights. The methodology is clearly articulated and justified, and the discussion effectively contrasts the strengths and limitations of each index. One area for improvement is the lack of microbiological data, which limits the ability to fully assess public health risks. Additionally, the inclusion of a summary visualization showing seasonal or spatial trends of key contaminants—such as heavy metals—would enhance data interpretation. Overall, this is a valuable contribution to water quality monitoring and management in protected areas, with practical implications for policy and conservation efforts.

Author Response

This manuscript presents a thorough and well-structured assessment of multi-depth water quality dynamics in the Ribnica Reservoir, using both the Serbian Water Quality Index (SWQI) and the Canadian Water Quality Index (CWQI). The dual-index approach is commendable, offering both localized and internationally comparable insights. The methodology is clearly articulated and justified, and the discussion effectively contrasts the strengths and limitations of each index. One area for improvement is the lack of microbiological data, which limits the ability to fully assess public health risks. Additionally, the inclusion of a summary visualization showing seasonal or spatial trends of key contaminants—such as heavy metals—would enhance data interpretation. Overall, this is a valuable contribution to water quality monitoring and management in protected areas, with practical implications for policy and conservation efforts

We sincerely appreciate your thorough analysis and constructive feedback. Your recognition of the dual-index approach, as well as the methodological clarity and practical implications of the study, is highly valued. We appreciate your observation and fully acknowledge the importance of microbiological data, particularly for a reservoir used for drinking water supply and located within a protected area. The data utilized in this study were obtained from official annual reports published by the Serbian Environmental Protection Agency, (authorized institution for water quality monitoring in Serbia) which defines the scope of monitoring and the parameters assessed each year. Given the limited number of sampling events (three measurements over two years) and the inconsistency in parameter coverage across different depths and profiles, it was not feasible to apply methods to assess seasonal and spatial trends of key contaminants such as heavy metals. While the authors had no influence over the selection of monitored parameters and number of sampling, the findings of this study underscore the need for a more systematic and comprehensive monitoring approach, including the introduction of continuous microbiological assessments. We hope that our results will contribute to future initiatives aimed at improving monitoring practices and ensuring the long-term protection of water quality in the Ribnica Reservoir.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Abstract

• Does not mention microbiological or seasonal limitations up front—these are essential to give context to the findings.

• Include at least one quantified index result to provide clarity on the extent of improvement or risk.

 

1. Introduction

• Acknowledges the lack of previous studies on Ribnica Reservoir but could strengthen justification by comparing the reservoir's hydrological importance to others studied.

• Strengthen the novelty of the research by including a short comparison to recent studies in Serbia or neighboring countries.
• Add references that compare temporal monitoring trends in other reservoirs to show where this paper fills the gap.

 

2. Materials and Methods

• The authors mentioned that there is no monitoring data exist for earlier or later years, this could be considered as a limitation.
• No mention of QA/QC procedures for sampling and lab analysis.

• Add a brief note on statistical methods used for analysis if applicable.

 

3. Water Quality Indices (WQI) Methodology

• There is no discussion on the rationale for weighting factors in SWQI. Are these standardized or based on expert judgment? Consider providing justification or source for each weighting factor in SWQI.
• State how many samples per depth were averaged.

 

4. Discussion

• Microbiological data (Total Coliforms) is missing—major gap acknowledged but not addressed with workaround.

• Some rounding inconsistencies (e.g., 0.0285 vs. 0.028) in Table (3) will harmonize decimal precision.
• “SWQI = 93” or similar scores are not interpreted with thresholds in-text (readers must refer to Table 2).

 

5. Conclusions

• Need more context on how thresholds for heavy metals were defined.
• Lacks discussion of cumulative ecological impacts (e.g., combined heavy metal toxicity).
• It is recommended to add section (6. Recommendations) to include the future way forward 

Comments for author File: Comments.pdf

Author Response

Abstract

• Does not mention microbiological or seasonal limitations up front—these are essential to give context to the findings.
• Include at least one quantified index result to provide clarity on the extent of improvement or risk.

We appreciate the reviewer’s insightful suggestions regarding the abstract. To enhance clarity and contextual depth, we have incorporated explicit mention of microbiological and seasonal limitations upfront, acknowledging their impact on the comprehensiveness of the water quality assessment. Additionally, we have included quantified index results from SWQI and CWQI to provide a more precise representation of both improvements and risks observed in the study. These revisions ensure that the abstract presents a balanced overview of the findings while addressing key methodological constraints.

1. Introduction

• Acknowledges the lack of previous studies on Ribnica Reservoir but could strengthen justification by comparing the reservoir's hydrological importance to others studied.
• Strengthen the novelty of the research by including a short comparison to recent studies in Serbia or neighboring countries.
• Add references that compare temporal monitoring trends in other reservoirs to show where this paper fills the gap.

We appreciate the reviewer’s suggestion to provide a broader comparative context regarding Ribnica Reservoir's hydrological significance and monitoring trends. In response to this feedback, we have expanded the introduction to incorporate a comparison with other studied reservoirs in Serbia, including Garaši, Vlasina and other reservoirs, highlighting the relative lack of systematic research on Ribnica despite its ecological and hydrological importance.

Additionally, we have strengthened the novelty of the study by referencing recent research from Serbia that have examined long-term water quality trends in artificial reservoirs.

 

1. Materials and Methods

• The authors mentioned that there is no monitoring data exist for earlier or later years, this could be considered as a limitation.
• No mention of QA/QC procedures for sampling and lab analysis.
• Add a brief note on statistical methods used for analysis if applicable.

 

We acknowledge that the absence of monitoring data from earlier and later years represents a limitation in assessing long-term trends in water quality. As noted in the manuscript, the available dataset was determined by the sampling conducted by the Serbian Environmental Protection Agency, and no additional data beyond the 2021–2022 period were accessible for analysis. This constraint restricts the ability to evaluate interannual variability and broader hydrological patterns.

Regarding QA/QC procedures, water sampling and laboratory analysis were performed according to standardized protocols established by the Serbian Environmental Protection Agency. These procedures ensure consistency in data collection and analytical precision, aligning with national and international water quality assessment methodologies. Summary of the used QA/QC procedures is presented in Table 1.

With respect to statistical analysis, given the limited dataset—comprising only three measurements across two years, with certain parameters inconsistently included in different sampling events—it was not feasible to conduct robust statistical assessments. The insufficient frequency of sampling and the lack of continuity in parameter measurement prevent meaningful application of trend analysis or inferential statistics. Instead, the study focuses on descriptive evaluation, comparing the water quality indices and parameter variations within the available data constraints. We explicitly clarified this point in the revised manuscript to ensure methodological transparency.

1. Water Quality Indices (WQI) Methodology

• There is no discussion on the rationale for weighting factors in SWQI. Are these standardized or based on expert judgment? Consider providing justification or source for each weighting factor in SWQI.
• State how many samples per depth were averaged.

 

We appreciate the reviewer’s observations regarding the weighting factors used in the Serbian Water Quality Index (SWQI) and the need for clarification on sample averaging.

To improve transparency, we have incorporated a detailed table outlining the weighting criteria applied in SWQI calculations. This table, originally presented in a previous publication (https://doi.org/10.3390/su17094074), systematically classifies water quality parameters according to their respective weight units (wᵢ), which directly influence the final SWQI score. The weighting factors in SWQI are established by the Serbian Environmental Protection Agency (SEPA) and are based on expert evaluations of each parameter’s significance in assessing water quality dynamics. Oxygen saturation, biochemical oxygen demand, and microbial contamination indicators (Total Coliforms) generally receive higher weights due to their direct relevance to water usability and ecological health. Conversely, temperature, pH, and electrical conductivity are assigned lower weights, as their variations, although influential, are primarily governed by natural processes within aquatic systems.

Additionally, in response to the reviewer’s request for clarification on sample averaging, we specify that where multiple measurements per depth were available (e.g., two sampling events in 2021), average values were calculated to provide a more representative assessment for that year. However, for 2022, only a single sampling event was conducted, meaning individual data points were used for analysis without averaging. This methodological constraint has been explicitly acknowledged in the revised manuscript to ensure clarity in data interpretation.

 

1. Discussion

• Microbiological data (Total Coliforms) is missing—major gap acknowledged but not addressed with workaround.
• Some rounding inconsistencies (e.g., 0.0285 vs. 0.028) in Table (3) will harmonize decimal precision.
• “SWQI = 93” or similar scores are not interpreted with thresholds in-text (readers must refer to Table 2).

We acknowledge the absence of microbiological data, particularly Total Coliforms, as a significant limitation in this study. While microbiological indicators are a critical component of comprehensive water quality assessments, no official data on Total Coliform concentrations were available for the Ribnica Reservoir during the study period. As such, our analysis was constrained to physicochemical parameters. However, we recognize the importance of microbiological monitoring, particularly for drinking water reservoirs, and emphasize the need for future studies to integrate systematic microbiological assessments. We have clarified this limitation in the discussion and reinforced the necessity for its inclusion in long-term monitoring strategies.

Regarding rounding inconsistencies in Table 3 (Table 5 after adding two new Tables) we have harmonized decimal precision across all reported values in all Tables to ensure consistency in numerical presentation.

Additionally, to improve readability, we have explicitly linked SWQI values to their corresponding categorical classifications (e.g., excellent, good, medium) within the text, eliminating the need for readers to refer back to Table 2 (Table 4 after adding two new Tables) for interpretation.

1. Conclusions

• Need more context on how thresholds for heavy metals were defined.

Thank you for this valuable suggestion. We add Table 2 with thresholds for heavy metals. Thresholds are defined by experts from Canadian Council of Ministers of the Environment who developed CWQI.

• Lacks discussion of cumulative ecological impacts (e.g., combined heavy metal toxicity).

We appreciate the reviewer’s valuable suggestion to expand the discussion on cumulative ecological impacts. In response, we have added a new paragraph to the Discussion section that addresses the interactive and potentially synergistic effects of heavy metals, with a focus on their combined toxicity and long-term ecological risks. This addition is supported by recent research highlighting how multiple metal exposures can intensify biological stress and disrupt aquatic ecosystems more severely than individual contaminants alone. We believe this revision strengthens the ecological relevance of our findings and underscores the importance of future integrated and multi-metal risk assessments, particularly in sensitive or protected environments.

• It is recommended to add section (6. Recommendations) to include the future way forward 

We appreciate your recommendation to include a dedicated Recommendations section for future research directions. After careful evaluation, we have opted to enhance the Discussion section instead, ensuring that our proposed research advancements and management considerations are seamlessly integrated into the broader context of our findings. Also, we add paragraph in Conclusion sections with recommendations. This approach provides a more unified and comprehensive analysis while maintaining the coherence of the manuscript.

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

The authors incorporated most of the reviewer’s comments and the manuscript is now in a good quality for publication. However, I have to minor comments under section 5. Conclusions:

• Need more context on how thresholds for heavy metals were defined. Also, these is a lacks discussion of cumulative ecological impacts (e.g., combined heavy metal toxicity).
• Figures (6-10) can be improved if the width of columns have been increased (minimizing the distance between columns)
•  

Comments for author File: Comments.pdf

Author Response

Response to Reviewer

The authors incorporated most of the reviewer’s comments and the manuscript is now in a good quality for publication. However, I have to minor comments under section 5. Conclusions:

• Need more context on how thresholds for heavy metals were defined. Also, these is a lacks discussion of cumulative ecological impacts (e.g., combined heavy metal toxicity).

Thank you for your comment. Threshold for heavy metals were defined by experts from Canadian Councils of Ministers of Environment (Table 2). We applied CWQI Calculator with defined thresholds. We expanded Conclusions in this way: we compared and discussed how heavy metals values in our study deviate from defined thresholds. Also, we added cumulative ecological impacts of heavy metals.

• Figures (6-10) can be improved if the width of columns have been increased (minimizing the distance between columns)

Thank you for the comment. We improved the Figures (6-10) according to your instructions.

Author Response File: Author Response.pdf