Ecological and Health Risk Assessment of Heavy Metals in Groundwater within an Agricultural Ecosystem Using GIS and Multivariate Statistical Analysis (MSA): A Case Study of the Mnasra Region, Gharb Plain, Morocco

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Congratulations for the Authors for the scientific work performed and clear presentation of the results. Still, I have minor remarks as listed below:

Line 16: The use of the acronym "Cd" for Degree of Contamination along with the chemical symbol of Cadmium (Cd) throughout the paper brings a bit of confusion to the reader. Clearly, Cadmium should stay as Cd, but maybe different acronym for Degree of Contamination is possible?

 

Line 47: acronym HMs for heavy metals is already introduced before in line 14

 

Figure 1:

a) I assume that the contour in upper left corner of the figure is Morroco, but it may not be clear for all readers from around the World. I suggest to add  the name "Morroco", the names of neighbouring countries, name of Atlantic Ocean and maybe even small part of Iberian Penisula with Southern parts of Spain and Portugal, as it is so close that it could fit into the picture.

b) Map of sampling wells in the lower right corner should be completed with important details and/or completely new figure (e.g. closeup on most contaminated southeastern area) should be prepared. At present the figure (and whole paper) is missing key information as follows:

- What is the shape of piezometric groundwater heads and resulting flow directions in the investigated area? (the information in lines 144-146 is too general)

- Is the main river in hydraulic connection with the groundwater aquifer?

- Is the river draining the groundwater or groundwater is mainly drained by the Ocean? 

- What is the flow direction in particular around the most contaminated wells P29 and P30? Why the most clean well P23 is so close to most contaminated well P29? Is it because of specific groundwater flow direction in this area?

- What is the exact shape and extent of the uncontrolled landfill? Is it the only probable groundwater contamination source zone? If not, what are the shapes of other suspected contamination source zones and possible contamination plumes in groundwater (thay have to be related to groundwater flow)

- What are the locations of the main receptors (like most important drinking water wells etc)? Could they be affected in future by contaminant migration?

 

Line 171-174: Usually, the filtration in field is performed before acidification in order to determine dissolved metal content. Alternatively, two samples are being collected: one sample is unfiltered but acidified for total metal content and the second sample is filtered and then acidified for the dissolved metal content. The procedure described by the Authors (acidification prior to filtration) is not typical because even if the filtration was done, it still leads to determining only total metal content (possible even without filtration) but it does not allow for dissolved metal content determination (because acidificatio is applied before filtration). What was the reason for such approach?

 

Conclusions: Please amend the conclusion to include the aspects of grounwater flow, contamination sources and plumes, receptors and how they might be affected (as explained in details above at the comments to Figure 1)

Best regards from the Reviewer!

 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Please consider the following points to revise the manuscript:

·       Title: It should be modified to include the "GIS" term in the title as seen in the following:

“Ecological and Health Risk Assessment of Heavy Metals in Groundwater within an Agricultural Ecosystem using GIS (Geographic Information System) approaches: A Case Study of the Mnasra Region, Gharb Plain, Morocco”

·       Abstract: It is fine but what heavy metal ions used in this study must be given in the abstract.

·       Introduction: Very good. As a reader, it is easy to understand what the authors tried to do based on the studies done so far in the literature.

·       Materials and Methods:

o   Information about the water equipment and water quality such as company, model, and resistivity!

o   Give more information about the chemicals used for the analysis and experiments such as company, purity, etc.

o   Information about all equipment used for the analyses such as company, model, measurement conditions, etc.

·       Results and discussion:

·       I think it will be a good idea to include a subtitle for each element.

·       Table 13: Include the units for each parameter.

·       Conclusions: Good.

·       Also, see the attached file for my corrections/comments on the manuscript.

·       the paper is written very well, however, there are some minor mistakes in the writing of the paper. Please correct them.

Overall, the paper looks fine, and can be accepted after the minor corrections to be published in the journal of “Water”.

 

Comments for author File: Comments.pdf

Comments on the Quality of English Language

·       The paper has some minor mistakes in the writing of the paper. 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

This study aims to evaluate the groundwater contamination by heavy metals (HMs) using GIS approaches, Multivariate Statistical Analysis (MSA), pollution indices (Heavy Metal Pollution Index (HPI), Metal Index (MI), Degree of Contamination (Cd), Ecological Risk Index (ERI), and Pollution Index (PI)), and human health risk assessment (HHRA). The results revealed significant variations in heavy metal concentrations across the study area, with the highest concentrations found in the southern and southeastern parts, characterized by intense agricultural activities and uncontrolled landfill. The manuscript is will written and the findings are significant. however, some comments should be addressed before any further recommendations:

1.      A suitable graphical abstract is missed. It is advisable to add a graphical abstract that reflects the methodology, analysis and results.

2. Some keywords such as Morocco, heavy metals and others should be linked by some words with the subject of the manuscript.

3- Suitable highlights should be added.

4. The novelty of the manuscript should be more addressed and highlighted at the end introduction. 

5. The organization of the manuscript should be revised. The figure or Table is usually mentioned then their discussion  must follow them. Their discussion should be after them and not before.

6. Some recommendations for future work can be added after the conclusions.

7- It should be noted that the toxicity of the studied metal ions is not the same. Some of them are highly toxic in spite of their low concentration such as Cr(VI) and As. Others become toxic at high concentration such as Fe(II). This fact should be mentioned in the discussion. In addition, some of the studied metal ions are of vital importance to our bodies like Fe(II). For this reason, The critical concentration of each ion should be indicated.

8. I ask the authors if they can use some equations to calculate the degree of ions toxicity beyond the critical limits. This will give some good comparison between the harmfulness of these ions.  

9.    It is not necessary to repeat the results in both the conclusion and the abstract.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf