Spatial and Multivariate Statistical Analyses of Human Health Risk Associated with the Consumption of Heavy Metals in Groundwater of Monterrey Metropolitan Area, Mexico

Round 1

Reviewer 1 Report

The purposes of the manuscript water-2255118 are to assess the carcinogenic and noncarcinogenic human health risks associated with exposure to metal(loid)s in groundwater used for consumption of Monterrey metropolitan area, Mexico.

The paper appears well-structured; however, some sections must be improved.  Therefore, I believe 

the manuscript should be published only after major revision.

Comments (R = row#):

R=104: Geogenic pollution it is little elaborated in the introduction. I recommend reading the following works and integrating this part: [1], [2]

R=141: why weren't the major elements analysed?

R=150: there is no geological framework with a petrographic and mineralogical description of the main lithologies outcropped. A geological map, also schematic of the area, should be inserted!

R=151: change geopatial in geospatial

R=175: why was kriging not used with an associated error map?

R=269: for this purpose, as per the previous comment, it would be very useful to refer to the different geochemical facies by studying the major elements! An example could be sulphate which could be related to arsenic and suggest an origin of arsenic from the dissolution of pyrite as evidenced by Fuoco et al 2022: [3]

R=283: the subdivision of the clusters is not clear, what is the dividing line? 20?

R=300: no explanation is given to the 3 PCs

R=342: chromium can also derive from the weathering of ophiolitic or mafic rocks, as evidenced by:, [4]:

R=353: describe the possible origins of the sulphate and As, which could also derive from sulfides such as pyrite rich in As. See for example the work of: [3]

Discussion and conclusions should be revised taking into account the previous comments

ADD THESE REFERENCES

[1]-Karunanidhi, D., Subramani, T., Roy, P.D. and Li, H., 2021. Impact of groundwater contamination on human health. Environmental Geochemistry and Health, 43(2), pp.643-647.

[2]-Fuoco, I., Marini, L., De Rosa, R., Figoli, A., Gabriele, B. and Apollaro, C., 2022. Use of reaction path modelling to investigate the evolution of water chemistry in shallow to deep crystalline aquifers with a special focus on fluoride. Science of The Total Environment, 830, p.154566.

[3]- Fuoco, I., De Rosa, R., Barca, D., Figoli, A., Gabriele, B. and Apollaro, C., 2022. Arsenic polluted waters: Application of geochemical modelling as a tool to understand the release and fate of the pollutant in crystalline aquifers. Journal of Environmental Management, 301, p.113796.

[4]-Fuoco, I., Figoli, A., Criscuoli, A., Brozzo, G., De Rosa, R., Gabriele, B. and Apollaro, C., 2020. Geochemical modeling of chromium release in natural waters and treatment by RO/NF membrane processes. Chemosphere, 254, p.126696.

Author Response

Response to Reviewer 1 Comments

The purposes of the manuscript water-2255118 are to assess the carcinogenic and noncarcinogenic human health risks associated with exposure to metal(loid)s in groundwater used for consumption of Monterrey metropolitan area, Mexico.

The paper appears well-structured; however, some sections must be improved.  Therefore, I believe 

the manuscript should be published only after major revision.

Comments (R = row#):

R=104:  Geogenic pollution it is little elaborated in the introduction. I recommend reading the following works and integrating this part: [1], [2]

Response 1: Works has been added and integrated in lines 75 - 82.

R=141: why weren't the major elements analysed?

Response 2: This work followed a similar methodology by [1] where major elements were not considered in the evaluation. However, we understand for future reference that these can be evaluated to better understand the dynamics and mineral dissolution.  

[1] Bux, R. K., Haider, S. I., Mallah, A., Solangi, A. R., Moradi, O., & Karimi-Maleh, H. (2022). Spatial analysis and human health risk assessment of elements in ground water of District Hyderabad, Pakistan using ArcGIS and multivariate statistical analysis. Environmental Research, 210, 112915.

R=150: there is no geological framework with a petrographic and mineralogical description of the main lithologies outcropped. A geological map, also schematic of the area, should be inserted!

Response 3: A section on the regional geology have been added in section 2.1 lines 117-144. Figure 2 is updated with the geology of the studied area and the well sampling locations.

R=151: change geopatial in geospatial

Response 4: Thanks for the observation. Typo error fixed.

R=175: why was kriging not used with an associated error map?

Response 5: Thanks for the observation. We chose not to use the kriging method since our results for high carcinogenic risk and indices where only slight high on two delimited sections of the studied area. However, our assessment only analyzes samples in one period. Therefore, we cannot assume that the joint probability distribution of the studied elements won’t change throughout space and time.  

R=269: for this purpose, as per the previous comment, it would be very useful to refer to the different geochemical facies by studying the major elements! An example could be sulphate which could be related to arsenic and suggest an origin of arsenic from the dissolution of pyrite as evidenced by Fuoco et al 2022: [3]

Response 6: The mentioned reference was included. However, the study could not perform major elements analysis at this moment. This suggestion will be considered for future work regarding the topic.

R=283: the subdivision of the clusters is not clear, what is the dividing line? 20?

Response 7: Figure 5 has been fixed. A phenom line at 22 helps identifying the clusters.

R=300: no explanation is given to the 3 PCs

Response 8:

R=342: chromium can also derive from the weathering of ophiolitic or mafic rocks, as evidenced by:, [4]:

Response 9: No ophiolites or mafic rock are identified in the area. Therefore, the evidenced Cr is not originated from the proposed sources.

R=353: describe the possible origins of the sulphate and As, which could also derive from sulfides such as pyrite rich in As. See for example the work of: [3]

Response 10:

Discussion and conclusions should be revised taking into account the previous comments

ADD THESE REFERENCES

[1]-Karunanidhi, D., Subramani, T., Roy, P.D. and Li, H., 2021. Impact of groundwater contamination on human health. Environmental Geochemistry and Health, 43(2), pp.643-647.

[2]-Fuoco, I., Marini, L., De Rosa, R., Figoli, A., Gabriele, B. and Apollaro, C., 2022. Use of reaction path modelling to investigate the evolution of water chemistry in shallow to deep crystalline aquifers with a special focus on fluoride. Science of The Total Environment, 830, p.154566.

[3]- Fuoco, I., De Rosa, R., Barca, D., Figoli, A., Gabriele, B. and Apollaro, C., 2022. Arsenic polluted waters: Application of geochemical modelling as a tool to understand the release and fate of the pollutant in crystalline aquifers. Journal of Environmental Management, 301, p.113796.

[4]-Fuoco, I., Figoli, A., Criscuoli, A., Brozzo, G., De Rosa, R., Gabriele, B. and Apollaro, C., 2020. Geochemical modeling of chromium release in natural waters and treatment by RO/NF membrane processes. Chemosphere, 254, p.126696.

Reviewer 2 Report

Please see the attached file herein.

Comments for author File: Comments.pdf

Author Response

Response to Reviewer 2 Comments

The paper titled "Spatial and multivariate statistical analyses of human health risk associated with the consumption of heavy metals in groundwater of Monterrey metropolitan area, Mexico. The article's content is vital for consumers in the studied regions. Furthermore, the manuscript is well-written. Therefore, I recommend this manuscript for publication after a major revision. I expressed some remarks below, believing they can help authors to improve the final version.

1. Please check the superscript and subscript for the ions all over the text.

Response 1: All subscripts and superscripts have been reviewed promptly.

2. Rewrite lines 25-28, 38-41, 45-48, 61-64, 76-79, 82-86, 311-316,

Response 2:  The suggested lines have been rewritten.

3. Please make the coordinate for Fig. 1 and Fig. 2.

Response 3: Coordinates were added to both figures.

4. Remove the duplicate paragraph (lines 250-260).

Response 4: The authors appreciate the observation. The duplicate paragraph was removed.

5. Table 3 is missing.

Response 5: The line in which Table 3 was written, was meant to be deleted. This was a typo error since there wasn’t any table 3 in the first place. We appreciate your observation for the mistake to be fixed.

6. Reconsider lines 397-399 with reference.

Response 6: Reference added as suggested.

7. Please rewrite positively ("sample collection season" is one reason that might influence the obtained results) from lines 403-409. Then, in the future, you might be able to clarify the difference due to the season.

Response 7: The observed lines have been positively rewritten. See lines 407 – 409. A two sampling period is proposed for further comparison (see lines 411-413)

Reviewer 3 Report

General Overview 

Authors of this manuscript have presented Spatial and multivariate statistical analyses of human health  risk associated with the consumption of heavy metals in ground-  water of Monterrey metropolitan area, Mexico. The idea is good. However, whole subject matter is not covered in the manuscript. There are some flaws, it needs more efforts to improve it further. Therefore, reviewer recommend major revision of this manuscript and publishing it only after improvement of the current version are made based on the following comments.

·         Please mention the practical significance of study

·         Introduce flowchart to show the methodology adopted

·         Many studies has been performed on subject matter. The novelty is still questionable?Justify

·         Please revise the manuscript carefully as there are many typo errors . Some of them are described as in the abstract line 27 ,29,30 numerical value (power of 10 should be superscript)

·         Please improve the quality of figure3, the dpi should be atleast 300

·         What is significance of figure 3 and 5?

·         Result and discussion should be written in separate heading that would be more easy to comprehend

·         Include heading and discuss regarding future research direction

·         Conclusion must be concisely written.

Author Response

Response to Reviewer 3 Comments

Authors of this manuscript have presented Spatial and multivariate statistical analyses of human health  risk associated with the consumption of heavy metals in ground-  water of Monterrey metropolitan area, Mexico. The idea is good. However, whole subject matter is not covered in the manuscript. There are some flaws, it needs more efforts to improve it further. Therefore, reviewer recommend major revision of this manuscript and publishing it only after improvement of the current version are made based on the following comments.

• Please mention the practical significance of study

Response 1: As an uprising and second most important economical hub in Mexico, the results from this study aid in better understanding the conditions that guarantee clean water for its population. Currently, the city is transitioning into Smart practices, meaning that future investments need to be supported by recent studies. 

• Introduce flowchart to show the methodology adopted

Response 2: A flowchart showing the conducted methodology is shown on Figure 2.

• Many studies has been performed on subject matter. The novelty is still questionable?Justify

Response 3: Many studies performed similar analysis in many places including Asia, Europe, Africa, and in North America. However, this kind of study have not yet performed in such an important city for Mexico like Monterrey in Nuevo Leon state. This city is the 2 commercial and industrial hub of Mexico. Therefore, it is vital to perform as many studies that can inform for guaranteeing and safeguarding the water resources of an important city where stakeholders, governments and decision makers are better informed as the area is transitioning into a Smart City as proposed by [1] and [2].

• Please revise the manuscript carefully as there are many typo errors . Some of them are described as in the abstract line 27 ,29,30 numerical value (power of 10 should be superscript)

Response 4: Superscripts have been carefully reviewed and corrected.

• Please improve the quality of figure3, the dpi should be at least 300

Response 5:

• What is significance of figure 3 and 5?

Response 6: Figure 3 shows that concentrations along the sampling wells are not normally distributed for each metal sampled in groundwater. Figure 5 depicts the groups of related metals after hierarchical cluster analysis, a phenom-line at 22 sub-classify into 3 groups.

• Result and discussion should be written in separate heading that would be more easy to comprehend

Response 7: The authors agreed to keep those together as it may affect the transitions of the text.

• Include heading and discuss regarding future research direction

Response 8: Future potential research has been headlined (lines 453-458)

• Conclusion must be concisely written.

Response 9: Reorganization of text was made.

[1] Huertas, J. I., Mahlknecht, J., Lozoya-Santos, J. D. J., Uribe, S., López-Guajardo, E. A., & Ramirez-Mendoza, R. A. (2021). Campus city project: Challenge living lab for smart cities. Applied Sciences, 11(23), 11085.

[2] Ramírez-Moreno, M. A., Keshtkar, S., Padilla-Reyes, D. A., Ramos-López, E., García-Martínez, M., Hernández-Luna, M. C., ... & Lozoya-Santos, J. D. J. (2021). Sensors for sustainable smart cities: A review. Applied Sciences, 11(17), 8198.

Round 2

Reviewer 1 Report

On the basis of the review done by the authors, in my opinion the paper is better than the precedent version

Reviewer 2 Report

The manuscript is now much improved. The authors have done a great job of responding to all comments over the article. This manuscript will make a good contribution to the scientific community as a research article. Thank you for all your efforts. I recommend to accept this article to publish.

Reviewer 3 Report

The authors have modified the manuscript as suggested.Now the modified version can be accepted in the present form