Pollution Levels and Potential Health Risks of Potentially Toxic Elements in Indoor and Outdoor Dust during the COVID-19 Era in Gómez Palacios City, Mexico

Round 1

Reviewer 1 Report

I have reviewed the manuscript titled “Changes in land use due to the pandemic and its effect on heavy metal contamination inside and outside homes". 

 

I do find it suitable for the Land but I have the following observations on this MS. 

 

The MS does contribute new in terms of methodology - a set of well-known methods have been applied for landuse changes areas land suitability analysis during pandemic and its sustainable management and these methods are important as well.

I see fruitful discussion on the generated datasets and a study area map should be improved. The introduction is improved and the scientific problem has been clearly identified and addressed but more recent work should be included.

I see little novelty in both scientific findings and methodological improvement.

The introduction is weak, and the method section is trivial and vague at some places.

Please improve the conclusion section as well and try to reduce it.

 

 

Author Response

I do find it suitable for the Land but I have the following observations on this MS. 

The MS does contribute new in terms of methodology - a set of well-known methods have been applied for land use changes areas land suitability analysis during pandemic and its sustainable management and these methods are important as well.

I see fruitful discussion on the generated datasets and a study area map should be improved.

The introduction is improved and the scientific problem has been clearly identified and addressed but more recent work should be included.

We improved the aim and included some references

I see little novelty in both scientific findings and methodological improvement.

A novel aspect in this article is the creation of technology (app) for citizens to take urban dust samples that will later be analyzed in the laboratory. This is now called "citizen science."

There are very few articles in which thresholds for decision-making are recommended, this is a strength of the article

The introduction is weak, and the method section is trivial and vague at some places.

We have included some references to support the information used in the introduction. We also rewrote the objective.

Please improve the conclusion section as well and try to reduce it.

The conclusions were rewritten and reduced

Reviewer 2 Report

Comments for author File: Comments.pdf

Author Response

Santoyo-Martínez et al. reported on the occurrence of potentially ecotoxic elements (namely: Zn, Ca, Cu, Rb, Fe, Ni, K, Sr, Ti, Y and Pb) in outdoor and indoor dust samples from Gómez Palacios City, Mexico during the pandemic year of 2020. This is an original contribution to the field that is potentially publishable. I have the following comments on the submission.

1. Title. Can be revised to read: Pollution levels and potential health risks of potentially toxic elements in indoor and outdoor dust during COVID-19 era in Gómez Palacios City, Mexico.

Ok, suggestion accepted, thanks.

2. Abstract

L12: activities outside the houses >> outdoor activities.

Ok, suggestion accepted, thanks.

Please;

1-List the number of samples and all the elements analyzed in the samples.

We measure many more elements with the mobile XRF equipment, but we only report the elements for which the equipment was calibrated.

2-Give the concentration ranges of the elements.

Table 1 contains the descriptive statistics

3. Introduction

L36: Coronavirus disease (COVID-19) is an infectious disease caused by the SARS-CoV-2 virus. Please revise.

Coronaviridae Study Group of the International Committee on Taxonomy of Viruses (2020). The species Severe acute respiratory syndrome-related coronavirus: classifying 2019-nCoV and naming it SARS-CoV-2. Nature microbiology, 5(4), 536–544. https://doi.org/10.1038/s41564-020-0695-z

Guo et al. (2020) The Origin, Transmission and Clinical Therapies on Coronavirus Disease 2019 (COVID-19) Outbreak—An Update on the Status. Military Medical Research, 7, Article No. 11. https://doi.org/10.1186/s40779-020-00240-0

Previous studies in Mexico should be mentioned, and also why the current study was necessary.

Ok, suggestions accepted. Thanks

4. Materials and Methods

L71: (SARS-CoV-2, previously known as 2019-nCoV)

Ok, thanks

L78-81: How were the samples collected and stored?

The following paragraph was included: The sampling of urban dust consisted of sweeping 1 m2 of the street surface and the total surface inside the houses. The samples were packaged in plastic bags and geo-referenced.

We also include the video link.

L85: (330) >> (n = 330).

Ok, thanks

Figure 1 is not clear.

We redid figure 1

Principal component analysis (PCA) and hierarchical cluster analyses should be done to allow for source apportionment of the heavy metals.

Okay, we include a PCA. Thanks

5. Results & Discussion

Discussion of PLI, Igeo and contamination factors should be in regards to the classification values suggested by Hakanson (1980) and Müller (1981)

Hakanson, L. (1980). An ecological risk index for aquatic pollution control. A sedimentological approach. Water Research, 14, 975–1001.

Müller, G. (1981). Die Schwermetallbelastung der Sedimenten des Neckars und Seiner Nebenflüsse. Chemiker-Zeitung, 6, 157–164.

We consider that the contamination factor is sufficient. More indices do not make a difference.

L298: Table S3 is not available for review?

The information from table S3 was included in figure 7

L304 or Fig. 5, delete “concentrations of the”

Ok, thanks

L315: You may not have to discuss this study results arguing that heavy metal contamination increased, yet there are no pre-pandemic records of the metal concentrations in dusts. Rather, I suggest comparing the results of this study with the reference values, and also previous studies in Mexican and other cities. Many publications are available for this.

Okay, we include a table with data on median concentrations of heavy metals measured in other Mexican cities.

6. Conclusions

L341: For you to deduce the sources, you need to perform PCA and cluster analyses as suggested.

Okay, we include a PCA .

Reviewer 3 Report

Santoyo-Martínez et al. reported on the occurrence of potentially ecotoxic elements (namely: Zn, Ca, Cu, Rb, Fe, Ni, K, Sr, Ti, Y and Pb) in outdoor and indoor dust samples from Gómez Palacios City, Mexico during the pandemic year of 2020. This is an original contribution to the field that is potentially publishable. I have the following comments on the submission.

1. Title

Can be revised to read: Pollution levels and potential health risks of potentially toxic elements in indoor and outdoor dust during COVID-19 era in Gómez Palacios City, Mexico.

2. Abstract

L12: activities outside the houses >> outdoor activities.

Please;

1-List the number of samples and all the elements analyzed in the samples.

2-Give the concentration ranges of the elements.

3. Introduction

L36: Coronavirus disease (COVID-19) is an infectious disease caused by the SARS-CoV-2 virus. Please revise.

Coronaviridae Study Group of the International Committee on Taxonomy of Viruses (2020). The species Severe acute respiratory syndrome-related coronavirus: classifying 2019-nCoV and naming it SARS-CoV-2. Nature microbiology, 5(4), 536–544. https://doi.org/10.1038/s41564-020-0695-z

Guo et al. (2020) The Origin, Transmission and Clinical Therapies on Coronavirus Disease 2019 (COVID-19) Outbreak—An Update on the Status. Military Medical Research, 7, Article No. 11. https://doi.org/10.1186/s40779-020-00240-0

Previous studies in Mexico should be mentioned, and also why the current study was necessary.

4. Materials and Methods

L71: (SARS-CoV-2, previously known as 2019-nCoV)

L78-81: How were the samples collected and stored?

L85: (330) >> (n = 330).

Figure 1 is not clear.

Principal component analysis (PCA) and hierarchical cluster analyses should be done to allow for source apportionment of the heavy metals.

 

5. Results & Discussion

Discussion of PLI, Igeo and contamination factors should be in regards to the classification values suggested by Hakanson (1980) and Müller (1981)

Hakanson, L. (1980). An ecological risk index for aquatic pollution control. A sedimentological approach. Water Research, 14, 975–1001.

Müller, G. (1981). Die Schwermetallbelastung der Sedimenten des Neckars und Seiner Nebenflüsse. Chemiker-Zeitung, 6, 157–164.

L298: Table S3 is not available for review?

L304 or Fig. 5, delete “concentrations of the”

L315: You may not have to discuss this study results arguing that heavy metal contamination increased, yet there are no pre-pandemic records of the metal concentrations in dusts. Rather, I suggest comparing the results of this study with the reference values, and also previous studies in Mexican and other cities. Many publications are available for this;

Aguilera et al. Heavy metal pollution of street dust in the largest city of Mexico, sources and health risk assessment. Environ Monit Assess 193, 193 (2021). https://doi.org/10.1007/s10661-021-08993-4

Aguilera et al. Heavy Metal Contamination (Cu, Pb, Zn, Fe, and Mn) in Urban Dust and its Possible Ecological and Human Health Risk in Mexican Cities. Front. Environ. Sci. 2022. https://doi.org/10.3389/fenvs.2022.854460

Liu et al. Pollution and health risk of potentially toxic metals in urban road dust in Nanjing, a mega-city of China. Sci. Total Environ. 2014, 522–531, 476–477.

Suvetha et al. Are we at risk because of road dust? An ecological and health risk assessment of heavy metals in a rapid growing city in South India. Environ. Adv. 2022, 7, 100165.

Kabir et al. A comprehensive assessment of heavy metal contamination in road dusts along a hectic national highway of Bangladesh: spatial distribution, sources of contamination, ecological and human health risks. Toxin Reviews. 2022, 41, 860-879.

Ali et al. Pollution characteristics and human health risks of potentially (eco)toxic elements (PTEs) in road dust from metropolitan area of Hefei, China. Chemosphere 2017, 181, 111–121.

Mondal, S.; Singh, G. Pollution evaluation, human health effect and tracing source of trace elements on road dust of Dhanbad, a highly polluted industrial coal belt of India. Environ. Geochem. Health 2021, 43, 2081–2103.

Cowan et al. A survey of heavy metal contents of rural and urban roadside dusts: comparisons at low, medium and high traffic sites in Central Scotland. Environ. Sci. Pollut. Res. Int. 2021, 28, 7365–7378.

Mohammed, F.S.; Crump, D. Characterization of Indoor/Outdoor Settled Dust and Air Pollutants in Damaturu, Nigeria. Int. J. Eng. Technol. 2013, 5, 104-108.

Moskovchenko, D.; Pozhitkov, R.; Ukarkhanova, D. Geochemistry of street dust in Tyumen, Russia: influence of traffic load. Environ. Sci. Pollut. Res. 2022, 29, 31180–31197.

6. Conclusions

L341: For you to deduce the sources, you need to perform PCA and cluster analyses as suggested.

Author Response

The paper is consistent with MDPI - Land and fits in the overall journal scope.

The title needs to be reconsidered because it does not reflect the area of the research. The reviewer suggests authors to add a subtitle.

Okay, the new title is “Pollution levels and potential health risks of potentially toxic elements in indoor and outdoor dust during COVID-19 era in Gómez Palacios City, Mexico”

The article is well structured. The article presents the results of the research according to the set methodology.

The aim of the article should be explicitly written in the text. That would make the reformulation of the article title much easy.

The new aim is “This study aimed to compare pollution levels and potential health risks of potentially toxic elements in indoor and outdoor dust during the COVID-19 era in Gómez Palacios City, Mexico.”

It is commendable that the Figure 4 is rotated and presented as landscape.

Ok, Thanks

The sentence in line 313 is not clear.

In the Discussion, besides the comparison of the results with the other authors results, it would be desirable to comment the differences in methodological approach in relation to other authors who dealt with the same issue.

It would be recommendable to put in a relation the external conditions in sites and increase contamination inside, and to determine if there are some rules (e.g. preview in additional table).

The authors should also highlight current limitations of their study.

It would be nice that authors give some possible guidelines for the reduction of the inside contamination that results from the conducted research.

In agreement with both observations, we have included a comparative table with data on heavy metals measured with FRX in other Mexican cities.

We have discussed the limitations of the task below and what remains to be done

Reviewer 4 Report

The paper is consistent with MDPI - Land and fits in the overall journal scope.

The title needs to be reconsidered because it does not reflect the area of the research. The reviewer suggests authors to add a subtitle.

The article is well structured. The article presents the results of the research according to the set methodology.

The aim of the article should be explicitly written in the text. That would make the reformulation of the article title much easy.

It is commendable that the Figure 4 is rotated and presented as landscape.

The sentence in line 313 is not clear.

In the Discussion, besides the comparison of the results with the other authors results, it would be desirable to comment the differences in methodological approach in relation to other authors who dealt with the same issue.

It would be recommendable to put in a relation the external conditions in sites and increase contamination inside, and to determine if there are some rules (e.g. preview in additional table).

The authors should also highlight current limitations of their study.

It would be nice that authors give some possible guidelines for the reduction of the inside contamination that results from the conducted research.

Author Response

The paper is consistent with MDPI - Land and fits in the overall journal scope.

The title needs to be reconsidered because it does not reflect the area of the research. The reviewer suggests authors to add a subtitle.

In agreement.

New title: Pollution levels and potential health risks of potentially toxic elements in indoor and outdoor dust during COVID-19 era in Gómez Palacios City, Mexico.

Subtítulo: Changes in land use due to the pandemic and its effect on heavy metal pollution

The article is well structured. The article presents the results of the research according to the set methodology.

Thanks

The aim of the article should be explicitly written in the text. That would make the reformulation of the article title much easy.

The new aim is “This study aimed to compare pollution levels and potential health risks of potentially toxic elements in indoor and outdoor dust during the COVID-19 era in Gómez Palacios City, Mexico.”

It is commendable that the Figure 4 is rotated and presented as landscape.

We agree.

The sentence in line 313 is not clear.

In the Discussion, besides the comparison of the results with the other authors results, it would be desirable to comment the differences in methodological approach in relation to other authors who dealt with the same issue.

Ok, we clarify that we compared with other results obtained with the same analytical techniques. The paragraph was as follows:

Comparing the concentrations of heavy metals in urban dust in this study with other Mexican cities using the same analytical technique, we found that Zn was in high concentrations indoors and outdoors.

It would be recommendable to put in a relation the external conditions in sites and increase contamination inside, and to determine if there are some rules (e.g. preview in additional table).

We agree. In the description of the results, we mentioned some patterns of land use that could affect the concentrations of heavy metals in the dust; however, at the site level, we did not find clear patterns.

The authors should also highlight current limitations of their study.

We agree.

New paragraph: During the COVID-19 pandemic, people stayed indoors, which could explain the higher concentrations of heavy metals in dust, which leads us to think that a decrease in the intensity of land use could lead to a reduction of heavy metal concentration in urban dust. However, this still needs to be tested with other post-pandemic studies.

It would be nice that authors give some possible guidelines for the reduction of the inside contamination that results from the conducted research.

New paragraph:

Two recommendations emerge from this work: a) The authorities should use the values of the concentrations of heavy metals in urban dust, generating prevention policies and implementing a monitoring system for pollution in urban dust, and improve the cleaning of the streets; b) Citizens should raise awareness about the dangers of urban dust, it is recommended to clean sidewalks and walls of houses, use special shoes for the exterior and interior, cleaning curtains, maintenance of furniture and walls inside the houses, use of chimneys, air cleaning systems, among others.

Round 2

Reviewer 3 Report

ACCEPT.

The words in Spanish (L400-402) should be placed in English