Human Health Risk and Quality Assessment of Spring Water Associated with Nitrates, Potentially Toxic Elements, and Fecal Coliforms: A Case from Southern Mexico

Round 1

Reviewer 1 Report

General Comments

1.      This research has many facets – from modeling monitoring networks, to characterizing the hydrochemical characteristics, to assessing health risk – and the authors do not make a solid case for why this is all packaged together as such. To be considered for publication, the paper should be re-written to include a more targeted case for what knowledge gaps are being filled, and only include the relevant information to fill those gaps. As it stands, the scope of the paper is too broad and it’s not targeted enough to have a coherent narrative. I included a number of detailed line edits, but would encourage the authors to consider the paper holistically and narrow down the scope and present a clear thesis that corresponds with that scope.

2.      The selection of the springs to use for the groundwater quality network needs to be put in better context throughout the manuscript. It is not clear who these networks are normally selected by, who uses them, and what the institutional frameworks are for water quality monitoring in this area. The authors present a new way to do the selection, but it’s not clear what the normal way of selecting springs would be in the absence of this method. The utility of this research needs to be grounded with this information, and a discussion of how it will be used. Further, the methods of how this selection was done are not clearly enough defined in the manuscript.

3.      In the revision, the introduction should define the knowledge gap that this research is aiming to fill; this is currently not well defined.

4.      The methods are not sufficiently complete to be replicated. Many details are missing, and sensitivity analyses should be included on the modeling to assess how the myriad of assumptions may affect the model outcomes. A number of detailed edits are include below to help identify the specifics that could be added.

5.      The use of the metric CCME-WQI isn’t appropriate for the data the authors have. This metric is intended to be used for routine monitoring with many replicated measures over a long time period. One of the parameters (F2, in Equation 5) represents the percentage of individual tests from a particular spring. In this case, there were only 2 testing times, so the only options for this parameter were 0%, 50%, or 100%. This doesn’t seem to be appropriate to use because of this.

6.      This paper does not list any limitations to the work.

7.      The results section also includes a lot of discussion points. These need to be either removed and placed in another section, or the results section needs to be labeled as “results and discussion”.

Specific Comments

INTRODUCTION

Define what a groundwater quality monitoring network is. This should include (with references) what it is, who it is used by, and how the

Line 58-61: The sentence “The assessment in the present study… through quality monitoring programs” doesn’t belong here. I suggest removing, or moving to the end of the introduction as a summary of the utility of the research.

Line 65: Is the word “redesign” correct, or should this be “design”?

Lines 65-73: This paragraph is very confusing. I suggest re-writing

Line 82-83: “the rural population of the aquifer”: re-write for clarity, as an aquifer doesn’t really have a rural population. Perhaps the rural population served by the aquifer?

Line 92: Mining activity is mentioned here. If mining is common and a consideration for water quality or health concerns, this should be mentioned prior to this point.

MATERIALS AND METHODS

Section 2.1 Study Area:

-        It would be helpful to include the population that lives in the area served by this aquifer.

-        Please explain how this study area was chosen for the research

-        There is a lot of detail here about the Aquifer, which can be shortened to be more concise, and/or related to the introduction section

Line 134: Please update to: “43 springs, four dug wells and one drilled well”

Line 139: I suggest removing the phrase “these activities are driven by groundwater”

Line 139-140: approximately 2.86 million cubic meters: please use the same units as in the previous sentences (hm^3/yr). Additionally, above it states that 2.06 hm^3/yr were used for public-urban use in 2011. It’s not obvious to the reader that this is an update of the previous earlier amount, and it may appear to be contradicting the earlier figure.

Line 149: please define AHP technique

Line 149: The initial letters in “Sample Collection and Data Analysis” do not need to be capitalized.

Line 149-150: the parenthetical (basic statistics, quality evaluation and hydrogeochemistry) is not needed; I suggest removing

Line 162: It seems like rather than rationale, this section describes the data sources

Line 185: Suggest replacing “vital liquid” with “water”

Section 2.3 Inventory of Springs:

-        Please include the number of springs that were identified by the REPDA database.

-        Please (briefly) clarify the process of the inventory. Were additional springs identified with the field work? How was the database information verified? Were there any in the database that were not able to be located?

Line 234-235: Step 1 does not seem necessary, as defining an objective is not really a step in the process.

Line 196-197: The line “the inventory fat the aquifer level….” Is not necessary and could be removed.

Line 241-242: Please clarify how the numerical values of 1-5 were assigned.

Line 265-266: The sentence “In this study it was 0.08…” is a result and is not needed here. However, the consistency rate should be defined and it would be helpful to list the criteria of what ranges are “acceptable”.

Lines 285-286: Please define how the low, medium, and high levels were determined. Is there a numeric cutoff value used?

Lines 285-286: please explain the relevance / utility of the suitability index. It’s not clear what this is used for

Section 2.5 Field Sampling and Data Analysis:

-        All parameters tested should be listed here in this section

-        Include additional detail about the microbial testing methods, including the media, transport conditions and time, and incubation conditions

-        Please list all QA/QC measures that were used, such as blank, duplicate, or other samples

Lines 292-297:

-        This description of the “spatial analysis” does not give enough information about what was done to get from the larger list of high-priority springs and end up with the final list of 20. Please describe this analysis and what considerations went into it.

-        “Social security” is listed as a consideration. Does this mean security of the data collection teams? Were any possible springs removed for this reason?

Line 301: Select another work to replace “Contemplated”

Lines 332-334: The justification for the use of the CCME-WQI metric doesn’t take into consideration the limited number of tests that were done for this research. It doesn’t seem like this metric is appropriate, based on one of three variables being dependent on the fraction of samples tested being acceptable, and there were only two sampling points.

Line 354: Please explain how the 17 parameters were selected for the CCME calculation

Line 371-372: Please include why/how these parameters were chosen for the health risk assessment.

Lines 388 and 585: please clarify whether adults were over 30 or under 30, as there are two conflicting mentions of this.

Lines 405-407: There is conflicting information here. Please clarify whether values <1 are no risk or low risk

Section 2.6 Health Risk Assessment: Please include a sensitivity analysis of these calculations, as there are many inputs and assumptions used.

Section 2.6.1: Fecal Coliform Risk: Please be more specific here that the risk isn’t of having fecal coliforms, but rather that the presence of fecal coliforms are indicates a risk of other pathogens in the water, and therefore a risk of diahreal disease from drinking that water. Further, this risk is not relevant to water that is not used for drinking, so therefore it is not relevant to the springs that are used for recreational water.

RESULTS

Section 3.1 Spring Inventory: Please include a description of what proportion of springs were protected/improved versus unprotected/unimproved. Were any connected to piped water systems, or was water always collected on site?

Lines 421-427: These first sentences aren’t relevant to the results and should be removed.

Line 427-428: “The inventory only considered those springs that were only source and with permanent flow”: this should be listed in the methods

Line 431: Please clarify if the 106 springs were the springs that were surveyed, or the springs listed in the database. The only number that is provided up until here was 43 springs, as listed in the introduction. Why are there so many more listed here? 

Lines 432-435: please clarify whether this information on use of springs was as obtained from the database, or whether it was based on what was found from visits to the springs – did these two things differ?

Line 441: Please remove the word “acceptable”. Also, confirm whether CR is consistency ratio or rate. Both are used.

 Line 447: Please remove the word “evenly”

Line 447-449: It is not clear what is meant by a “good qualitative measure for decision making”. The selection of water points doesn’t strike me as a measure, and who are the decision-makers referenced here? 

Lines 497-498: The first sentence isn’t needed. Please remove.

Lines 498-500: The results of the t-test comparing the wet and dry season results should be listed after the summary statistics of all the parameters. Also, p-values should be included with the statistical test, as well as the means and standard deviations of the compared metrics.

Lines 500—502: The sentence” The water quality assessment … primary contact” Is repetitive and not needed.

Lines 504-545: These results can be written far more concisely. Please revise this whole section.

The word “oscillate” may be replaced with the word “varied”

Section 3.4: Throughout this section, it would be more informative to use summary statistics like the % of springs that were in different categories, rather than listing the codes for all the individual springs. 

Section 3.5: Please revise this section. Fecal coliform is used as an indicator organism for fecal contamination, which may cause diarrheal disease. The levels of contamination are indicative of diarrheal disease risk.

CONCLUSIONS

Line 645-646: The phrase “during the rainy season” should be relocated to after the word nitrates.

Lines 658-659: “…especially due to methemoglobinemia in infants”: This statement is not backed up by any of the research.

Lines 661-662: The first sentence (“The risk index for coliforms…”) is not an accurate depiction of the fecal coliform results. The risk index was not medium in the dry season; instead, the highest frequency was samples in that diarrheal disease risk category.

FIGURES AND TABLES
Figure 2: The arrows aren’t  appropriately organized in this figure to display the inputs as being the inputs into the processes. I suggest rearranging this figure to be more logical in what is an input and output.

Figure 3: I do not find this figure very helpful on its own, so I would consider removing it. It is full of undefined terms like “Fuzzy (1-250)”. If it is to be kept, the steps should all be written as phrases in the same form (like action verbs) and be more descriptive (for example, “Evaluation” on its own doesn’t give the reader any idea of what is being evaluated or why). Additionally, I suggest removing Step 1, as this isn’t really a step in the process (it’s just listing the objective).

Table 2: Please add the limits for recreational waters in addition to drinking water, as it was listed that these limits were used in the CCME-WQI calculation for the two springs used for recreational uses.

Table 3: Consider reformatting the table so the parameters are all in individual rows, instead of having the column names repeated. Additionally, please provide references for all the recommended values/inputs

Table 4: Change Zero to <1 CFU/100mL. Please update the table caption to indicate this is referring to diarrheal disease risk.

Figure 4: Please update the caption to be more descriptive of what is shown in the figure.

Tables 5&6:

-        Include the month and year of sampling in each table caption.

-        The individual readings from each spring are not that informative to the reader. If the authors feel there is some utility of including every result, it can be in the supplementary information

-        These tables would be better with summary statistics for each parameter, including the min, max, mean, SD, and % of samples within the recommended ranges according to the different referenced guidelines/standards

-        Additionally, I recommend grouping the springs as those intended for drinking and those intended for recreational/other uses. Then the appropriate maximum limits for drinking or recreational use can be included and used to compare for the non-drinking water springs.

Figures 8&9: The text and color coding are too small to be informative. It doesn’t appear that the spatial distribution is that important, so I suggest changing these to be summary tables instead of maps.

Figure 10:

-        I recommend a 2D bar graph instead of 3D to limit misinterpretation.

-        Include a legend or description of the numeric CFU limits that correspond to the risk levels

-        Change “simple risk” to “low risk”

-        Label this as Diarrheal disease risk (not risk for fecal coliforms) from drinking the water

Author Response

Please see the attachment

Thank you!

Author Response File: Author Response.pdf

Reviewer 2 Report

Manuscript ID: Water-2344168

Maisari Utami and co-authors reported " Health Risk and Quality Assesment of Spring Water Associated with Nitrates, PTE, and Fecal Coliforms: A Case from Southern México".    Although the topic is interesting but some important aspects were not performed. Following comments should be addressed before possible consideration for publication in worthy Journal of Water. I believe it will not take a long for the authors to work on this revision.

1.      In abstract various abbreviations were used like HQ and HI. Use full form when write 1^st time and then abbreviation be used throughout the manuscript.

2.      Abstract is like a student report work it should be in compiled form and add more numerical values added.

3.      There are so many typo grammatical errors in whole manuscript, should be revised by some native speaker and formatting should be checked.

4.      Manuscript is not in proper format, like some tables (Table 1).

5.      For novelty, some latest papers about water analysis and their treatment through different techniques should be added like https://doi.org/10.1080/03067319.2020.1846732, Inorganic Chemistry Communications 145 (2022) 110008

6.      In conclusion add numerical values from results.

7.      Authors should briefly explain the methods for the determination of different minerals, metal ions and coliforms.

Author Response

Dear Reviewer!

Please see the attachment.

Thank you!

Author Response File: Author Response.pdf

Reviewer 3 Report

Dear authors, thank you for submitting the manuscript to the journal of Water. Its topic is very interesting. However, the current version of the paper suffers from a number of weaknesses related to the empirical strategy used. I have the following comments/questions for the authors:

Title

·         Please correct "Assesment" to Assessment.

·         Please don’t use abbreviation in the title "PTE".

·         Please correct the title to "Health Risk and Quality Assessment of Spring Water Associated with Nitrates, Potentially Toxic Elements, and Fecal Coliforms: A Case from Southern México".

Abstract

·         Line 19. "The Buenavista de Cuellar (ABC)" Is this correct?

·         Line 21. Please add the aim of the study before the methods used.

·         Include a line or two about the novelty and the research gap that you are addressing.

·         The abstract could be more specific. I suggest the authors should organize the abstract as well as main text in four sections, namely: scope, objectives, methods, results, conclusions. Also, abstract section should be completed with the results of the study. Don’t use abbreviation on the first time. Define full form for the first time than after use abbreviation only (Please check in the entire manuscript).

·         The abstract section needs a lot of improvement in scientific writing. There are many sentences which are not properly presented.

·         Add important results in the abstract section.

·         What are the practical implications of your research (how can the results be utilized by e.g., readers, community)?

·         The authors ought to re-write the abstract so that it briefly presents the problem at hand, objectives of the study, methods used to achieve the objectives in logical order. Also, abstract section should be completed with the results of the study.

 Introduction

·         In introduction chapter please focus on problem generally, on the basis of examples in the whole World, not your study area.

·         Add some facts and figures of groundwater quality around the globe in your introduction.

·         The research gap and the research objectives were not clear in the submission. A clear list of previous studies should be provided to clearly identify the research gap in the research and also highlight the novelty of the research.

·         Add some recent article to make your introduction more attractive and strong. I propose to add this survey method in the overview section of the introduction section, based on the latest literature. Please replace old citations (if it is possible) or add citations of newest literature.

https://doi.org/10.3390/w15061216

https://doi.org/10.3390/w14030483

https://doi.org/10.3390/w14152311

·         The authors should formulate hypothesises, and add to the end of the section introduction.

Materials and Methods

Study area

·         Describe all the features of the study area in brief including climate, topography, geology, and hydrogeology?

·         Would you please give more information about The Buenavista de Cuellar Aquifer (e.g., max depth, average precipitation and evaporation)?

Field Sampling and data analysis

·         Please give detailed information on water samplers (e.g., accuracy, manufacturer).

·         Sampling locations were selected carefully within the Buenavista de Cuellar aquifer to have a good representation of the spatial variability of quality indicators across-section of water quality monitoring. What criteria where analyzed to select this locations?

·         Please provide detailed detection methods and quality control results?

·         Please support your methods by providing appropriate references or give the guidelines used to analyze the water quality parameters.

·         Please support your methods by providing appropriate references or give the guidelines used and equations.

·         How did you do quality control (QC) and quality assurance (QA) on the obtained data to validate the conclusions?

 Results in line 419 (Please modify this title to "Results and Discussion")

·         You should think how transformational the research is likely to be should be made so that the outcome of the work will have an impact on the community/society facing given sustainability related challenges?

·         Write the practical applications of your work in a separate section, before the conclusions and provide your good perspectives.

·         What are the likely research impacts of this work globally, nationally and locally?

·         What long-term impacts will it have on environmental protection and the wider public or the field following the completion of the research?

·         Implications: The authors must develop a subsection for theoretical and practical implications. Implications could be enhanced by providing the results of your work towards the development and adoption of the current findings.

Conclusion

·         Conclusion section seems to be repetition of the results section. Huge modifications are required. Please make sure your ‘conclusion’ section underscores the scientific value added of your paper, and/or the applicability of your findings/results, as indicated previously. Please revise your conclusion part into more details. Basically, you should enhance your contributions, limitations, underscore the scientific value added of your paper, and/or the applicability of your findings/results and future study in this section.

·         Concise the text in conclusion and add future work in order to recommend your work.

·         Shorten the length of each and every paragraph by adding only relevant and major findings in your study.

Please respond to all of those comments in the revised manuscript by pointing out precisely and concisely on which page and in which line you have incorporated your response one by one.

Comments for author File: Comments.docx

Author Response

Dear reviewer!

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

I commend the authors on a much-improved manuscript with this revision.

However, I cannot recommend that this manuscript be accepted in its current form. I still have an issue with the use of the CCME-WQI metric. Many thanks for including the reference document from the Canadian government (CCME WATER QUALITY INDEX 1.0 USERS MANUAL). This users manual states that “The calculation of the CCME WQI requires that at least four variables, sampled a minimum of four times, be used.” In this research, seventeen parameters were used, but only at two sampling points: wet and dry season. Therefore, this isn’t a proper use of the metric, the results should be presented in another manner.

I also recommend the inclusion of limitations to the research, which was not addressed.

Author Response

The authors are grateful to the reviewer for their comments and suggestions for the improvement of the article.

Dear reviewer, we have carefully examined the CCME-WQI user manual and we agree with your observation. Unfortunately, we do not have more Information that allows us to correctly apply the CCME-WQI index, so we decided to remove this section within the paper. In this regard, it is important to emphasize that the modification does not have an impact on the stated objective, since the evaluation of water quality exists within the work.

The limitations are mentioned in the lines: 978 - 980 y 985.

Between lines 1011 and 1015 the recommendations were improved.

Finally, the some possible uncertainties are mentioned in the lines: 1004 -1009.

Reviewer 2 Report

Accept

Author Response

The authors are grateful to the reviewer for their comments and suggestions for the improvement of the article.

Reviewer 3 Report

In my opinion this paper is an interesting study and authors have evaluated the risk to human health by oral and dermal routes in adults and children based on the design of a spring water quality monitoring network by using the MCE in combination with Geographic Information Systems approach.

The article is written correctly, includes a discussion of the research findings, and a good review of the literature. The results are presented in a clearly structured manner. The paper has a logical structure and clearly describes the methodology. The manuscript has been significantly improved and can now be accepted in current form.

Author Response

The authors are grateful to the reviewer for their comments and suggestions for the improvement of the article.

Round 3

Reviewer 1 Report

To the authors: thank you for looking into this issue and revising the manuscript accordingly.