Polychlorinated Biphenyls in the Snow Cover of South-Eastern Kazakhstan

Round 1

Reviewer 1 Report

This paper investigated the distribution of polychlorinated biphenyls (PCBs) in the snow cover of southeastern Kazakhstan. Concentrations of PCBs from different years (2014, 2015, 2018-2020, 2021) and areas (Talgar city and Almaty city, Almaty agglomeration, Territory of Ili River Delta and Ili-Balkhash State Natural Reserve) are discussed in detail. This work is meaningful and will provide basic data for the toxicity assessment of PCBs on environment and human beings. However, further revision should be addressed before publication. My detailed comments are as follows:

1. The Introduction is too verbose and should be refined, several paragraphs with no important information (such as line 61-68 and 79-74) can be deleted. Relative paragraphs can be put together and re-organized in the context to make it more logical.

2. It may be more appropriate to list several toxic effects of PCBs on environment and human beings in introduction.

3. For line 106, 108 and 111, references should be put at the end of the sentences, the same question may exit for other references, please check it again.

4. How do you determine the monitoring time and sites?  Although these three areas in this paper all located in the southeastern Kazakhstan, it seems more meaningful if the data was acquired from one site of different years (for example, monitoring the PCBs concentrations in Talgar and Almaty city from 2014 to 2021), or from different sites in the same year (for example, monitoring the PCBs concentrations in these three areas in 2021). The data in this paper was from different areas and different years, and they are not comparable.

5. For line 173-177, the font should be changed in accordance with other parts of this paper.

6. Generally the gas flow varied from 0.8-1.2 mL/min in GC methods, please verify the data in line 182 (38 mL/min), is this a mistake?

7. According to my experience, “dm³” seldom appears in scientific papers, “L” is a more common unit, so changing the unit ‘μg/ dm³’ to ‘μg/L’ seems to be more appropriate.

8. For line 200, according to Table 2, the maximum PCBs concentration was 0.66 in the snow from Almaty, rather than 0.65.

9. The Y-axis of figure 2 seems not correspond to the line, for example: the point (2014.12.08 Almaty 3.79) seems to be 2.0 from Y-axis.

10. From Table 1, Table 2 and Figure 2, we can see that PCBs concentrations were higher in Almaty city than Talgar city in most cases, however, the authors gave the opposite statement in line 216-219, why?

11. The caption of the right Y-axis of Figure 7 (height above sea level) can be changed to ‘altitude’.

12. In the section of Results, there is no 3.2, so secondary title can be used in this section instead of tertiary title.

13. The section of Conclusions was also too verbose and should be refined, some unimportant information can be deleted (such as line 446-455 and 462-471).

Comments for author File: Comments.docx

Author Response

Response to Review 1

Thank you for your review and comments! We have tried to improve the manuscript, based on your advises.

 

Open Review

(x) I would not like to sign my review report
( ) I would like to sign my review report

English language and style

(x) Extensive editing of English language and style required
( ) Moderate English changes required
( ) English language and style are fine/minor spell check required
( ) I don't feel qualified to judge about the English language and style

 

	Yes	Can be improved	Must be improved	Not applicable
Does the introduction provide sufficient background and include all relevant references?	(x)	( )	( )	( )
Are all the cited references relevant to the research?	(x)	( )	( )	( )
Is the research design appropriate?	( )	(x)	( )	( )
Are the methods adequately described?	( )	(x)	( )	( )
Are the results clearly presented?	( )	(x)	( )	( )
Are the conclusions supported by the results?	(x)	( )	( )	( )

Comments and Suggestions for Authors

We have improved the research design, the methods description and the results presentation

This paper investigated the distribution of polychlorinated biphenyls (PCBs) in the snow cover of southeastern Kazakhstan. Concentrations of PCBs from different years (2014, 2015, 2018-2020, 2021) and areas (Talgar city and Almaty city, Almaty agglomeration, Territory of Ili River Delta and Ili-Balkhash State Natural Reserve) are discussed in detail. This work is meaningful and will provide basic data for the toxicity assessment of PCBs on environment and human beings. However, further revision should be addressed before publication. My detailed comments are as follows:

1. The Introduction is too verbose and should be refined, several paragraphs with no important information (such as line 61-68 and 79-74) can be deleted. Relative paragraphs can be put together and re-organized in the context to make it more logical.

We have deleted paragraphswith less important information, such as line 61-68 and 79-74).

We have put together paragraphs and re-organized the context. We hope it is more logical now! Due to the fact that this information does not contain important information, we have deleted these paragraphs.

2. It may be more appropriate to list several toxic effects of PCBs on environment and human beings in introduction.

We have listened several toxic effects of PCBs. Additional information has been added to this paragraph about the negative impacts of polychlorinated biphenyls on the environment and on humans, with references to the World Health Organization!

3. For line 106, 108 and 111, references should be put at the end of the sentences, the same question may exit for other references, please check it again.

We have changed the references positions.

4. How do you determine the monitoring time and sites? Although these three areas in this paper all located in the southeastern Kazakhstan, it seems more meaningful if the data was acquired from one site of different years (for example, monitoring the PCBs concentrations in Talgar and Almaty city from 2014 to 2021), or from different sites in the same year (for example, monitoring the PCBs concentrations in these three areas in 2021). The data in this paper was from different areas and different years, and they are not comparable.

Of course, we know, it would be better to have data from the same location from different years. However, snow cover data sampling depends on the occurrence of snow. In seasons and years without or not enough snow, snow cover sampling was not possible.

Due to the fact that, PCB data in snow cover even in Kazakhstan are very rare, we used all data, which we could collect. For future winter seasons we plan to repeat snow cover sampling for PCB concentration determination, to extend the knowledge.

5. For line 173-177, the font should be changed in accordance with other parts of this paper.

Thank you! We have changed the font.

6. Generally the gas flow varied from 0.8-1.2 mL/min in GC methods, please verify the data in line 182 (38 mL/min), is this a mistake?

 

We have verified the data. We have carefully checked the gas flow rate for this chromatograph and it corresponds to what was written before, i.e. 38 ml/min).

We have once again checked the technical documentation for the chromatograph used, and made reference to identical methods of measurement, and so we will stick to the values that were stated in the earlier version.      

For information, ISO 6468-2003 is identical to ISO 6468:1996 "Water quality - Determination of certain organochiorine insecticides, polychlorinated biphenyls and chlorobenzenes - Gas chromatographic method after liguid-liguid extraction". Determination of certain organochlorine insecticides, polychlorinated biphenyls and chlorobenzenes. Gas chromatographic method after liquid-liquid extraction").

 

7. According to my experience, “dm³” seldom appears in scientific papers, “L” is a more common unit, so changing the unit ‘μg/ dm³’ to ‘μg/L’ seems to be more appropriate.

 

Thank you! We have changed the unit all over the manuscript.

 

8. For line 200, according to Table 2, the maximum PCBs concentration was 0.66 in the snow from Almaty, rather than 0.65.

 

Thank you! On this issue the authors of the manuscript cannot agree with the reviewer's comment, due to the fact that in fact the value of 0.65 is correct, please check again in Table 2.

 

9. The Y-axis of figure 2 seems not correspond to the line, for example: the point (2014.12.08 Almaty 3.79) seems to be 2.0 from Y-axis.

 

Thank you! We have improved this.

 

10. From Table 1, Table 2 and Figure 2, we can see that PCBs concentrations were higher in Almaty city than Talgar city in most cases, however, the authors gave the opposite statement in line 216-219, why?

Thank you for your comment! We have improved this.

11. The caption of the right Y-axis of Figure 7 (height above sea level) can be changed to ‘altitude’.

Thank you! We have changed it to „Altitude above sea level“.

12. In the section of Results, there is no 3.2, so secondary title can be used in this section instead of tertiary title.

Thank you! You are right! We have changed the section numbering into: 3.1, 3.2, 3.3

13. The section of Conclusions was also too verbose and should be refined, some unimportant information can be deleted (such as line 446-455 and 462-471).

Thank you! We have made the conclusion shorter, and we have added some additional conclusions.

 

peer-review-20946603.v1.docx

Submission Date

11 July 2022

Date of this review

31 Jul 2022 16:15:21

 

Revision: 9th + 15th August 2022

Author Response File: Author Response.pdf

Reviewer 2 Report

1. The paragraphs in Introduction section is OK. However, in this part, authors should add more details about the previous studies of others. In the original context, no detailed information about the historical references or studies were presented, which should be added more. Especially the significance and hazardous-/health-/environmental management implications of this study should be highlighted briefly at the beginning. It needs to be addressed what the originality or novelty of the present work is in comparison with these previous works.
2. The authors mentioned that there is no standard analytical method, and even no reference materials. The results did not compare with anything that recognized. The key factor of accuracy is uncertain.

3. What is the most advantage of the proposed method compared with previous methods?
4. How is the selectivity of the present method? A selective factor should be provided in the manuscript.

5. A comparison between the proposed method and other methods should be provided in the manuscript.
6. Based on the outcome of the present study, the author(s) should recommend the extension of the present study as future scope of study. Especially in industrial section.
7. The conclusion should be expanded and the meaning of this paper should be mentioned in detail. This part should include and report the major outcomes of the study emphasizing towards fulfillment of the scope of the study.
8. Author(s) are suggested to elaborate the conclusion drawing major inferences from the results followed by the secondary conclusions/recommendations reached through the critical analysis/investigation.

9. Some figures need to improve high solution.

10. Also, for the English writing, it's better to invite a native-speaker to help and improving this grammar and expressions.

Author Response

Response to Review 2

Thank you for your review and comments! We have tried to improve the manuscript, based on your advices.

Review2

Open Review

( ) I would not like to sign my review report
(x) I would like to sign my review report

English language and style

( ) Extensive editing of English language and style required
( ) Moderate English changes required
(x) English language and style are fine/minor spell check required
( ) I don't feel qualified to judge about the English language and style

 

	Yes	Can be improved	Must be improved	Not applicable
Does the introduction provide sufficient background and include all relevant references?	( )	(x)	( )	( )
Are all the cited references relevant to the research?	( )	(x)	( )	( )
Is the research design appropriate?	( )	( )	(x)	( )
Are the methods adequately described?	( )	( )	(x)	( )
Are the results clearly presented?	( )	(x)	( )	( )
Are the conclusions supported by the results?	( )	( )	(x)	( )

 

 

We have tried to improve the research design, the mezhods and the conclusions

We have described the samle collection of the snow cover samples in detail more clear, including, why we have used (and not used) snow samples for each station and for each (not each) year. Additionally, we have described  the laboratory analyses more in detail, and an updated standard in Kazakhstan, which is identical to the international standards on this topic of research, is given.

We have improved the conclusions, making some conclusions more short, and adding some substantial descriptions as new conclusions.

 

Comments and Suggestions for Authors

1. The paragraphs in Introduction section is OK. However, in this part, authors should add more details about the previous studies of others. In the original context, no detailed information about the historical references or studies were presented, which should be added more. Especially the significance and hazardous-/health-/environmental management implications of this study should be highlighted briefly at the beginning. It needs to be addressed what the originality or novelty of the present work is in comparison with these previous works.

We have included more studies from other authors, including a short characterization of some highlights of other studies.

We have included several toxic effects of PCBs regarding the hazardous-/health-/environmental management implications

Based on the extended characterization of the state of knowledge and the knowledge gaps, we tried to highlight the originality and novelty of our present work.

2 The authors mentioned that there is no standard analytical method, and even no reference materials. The results did not compare with anything that recognized. The key factor of accuracy is uncertain.

Sorry, this was a mistake, which  we have improved now. We know that there exist standards in international publications. We have used this knowledge too. Therefore our methods and results are comparable with results from other authors, even because we have used the same methods and laboratory analyses. What we have meaned in our original manuscript is, that there was no standard in Kazakhstan before our study took place.

Methods for analyzing polychlorinated biphenyls exist in Kazakhstan, and they meet international standards. We cited this in the text, in addition, it should be noted that research on persistent organic pollutants in the aquatic environment, practically, except for the authors of this manuscript is not engaged.

 What is the most advantage of the proposed method compared with previous methods?

The most advantage is that we have demonstrated an approach, which easily can become a standard for future analyses.

Indeed, the approaches that are presented in this manuscript are interesting for science in general, since it is in the snowpack that there are quite few meassurements and studies.  It is our hope that this will be the impetus for further research in other areas as well.

4. How is the selectivity of the present method? A selective factor should be provided in the manuscript.

The location of the sampling point on a large territory, as a rule, is performed by the sampling square method, thus, the territory is divided into several tens of squares. In each square it is necessary to take samples for more reliable assessment of the degree of pollution. Such an approach is also justified for constructing maps of the distribution of pollutants in the snow cover. (it is possible that the question concerns the selectivity of sampling points).

5. A comparison between the proposed method and other methods should be provided in the manuscript.

We do not exactly know the intension of this comment. However, we tried to compare described field or sampling methods and laboratory methods. In the text of the manuscript, literature sources where similar studies were done, methods and approaches are identical.  

6. Based on the outcome of the present study, the author(s) should recommend the extension of the present study as future scope of study. Especially in industrial section.
   
   

You are right! Thank you for your advice! We have added such points into the conclusions.

7. The conclusion should be expanded and the meaning of this paper should be mentioned in detail. This part should include and report the major outcomes of the study emphasizing towards fulfillment of the scope of the study.
   
   

You are right! Thank you for your advice! We have added such points into the conclusions.

 

8. Author(s) are suggested to elaborate the conclusion drawing major inferences from the results followed by the secondary conclusions/recommendations reached through the critical analysis/investigation.

 

We have re-structered the conclusions, (1) adding the inferences (first conclusions) comming from the results, and adding the (2) secondary conclusions as recommendations both for science and for state control / monitoring and practice.

 

9. Some figures need to improve high solution.

We have tried to rework / to improve the resolution of some figures (new Fig.1-7)

10. Also, for the English writing, it's better to invite a native-speaker to help and improving this grammar and expressions.

A nearly native speaker has checked the Englisch grammar and expressions.

 

Submission Date

11 July 2022

Date of this review

23 Jul 2022 15:43:15

 

Revision: 8th +15th August 2022

Author Response File: Author Response.pdf

Reviewer 3 Report

Thank you for the opportunity to review a manuscript entitled: "POLYCHLORINATED BIPHENYLS IN THE SNOW COVER OF SOUTH-EASTERN KAZAKHSTAN." 

The topic of the manuscript is of interest and novel. The results are interesting and well described. However, there are a few things that should be improved before publication. My detailed comments are presented below: 

1. The introduction is well written and adequately describes the selected regions and the risks imposed by PCBs; however, some of the literature there is quite old and could be updated.

2. Please fix the headings in the materials and methods to fit with the journal guidelines. 

Figure 1 is not necessary, especially in a non-English language. Perhaps the authors should consider moving it into supplementary data. Other than that, the methodology is adequately described.

 

3. Results: The description of the results is nicely written and contains many details. Hoverer, the figures could be improved. Since the journal publishes in electronic form, could the authors present the data in figures 3 & 4 in color? Either comparing changes between years in the same point by using different colors or gradients the severity of the problem? 

The same comment for figure 5 - this map is crucial and could also be referenced in the methodology section. Perhaps the authors could mark different points with different colors and then use the same colors for the graphs for the exact location? For example: if I'm interested in Big Almaty Lake and it has a green color on the map, I'm looking for green bars in the results graphs. I think the manuscript would greatly benefit from it when it comes to its readability. 

The writing part of both the results and discussion section is proper and well proofread. 

Author Response

Response to Review 3

Thank you for your review and comments! We have tried to improve the manuscript, based on your advices.

 

Review 3

Open Review

( ) I would not like to sign my review report
(x) I would like to sign my review report

English language and style

( ) Extensive editing of English language and style required
( ) Moderate English changes required
(x) English language and style are fine/minor spell check required
( ) I don't feel qualified to judge about the English language and style

 

	Yes	Can be improved	Must be improved	Not applicable
Does the introduction provide sufficient background and include all relevant references?	( )	(x)	( )	( )
Are all the cited references relevant to the research?	( )	(x)	( )	( )
Is the research design appropriate?	(x)	( )	( )	( )
Are the methods adequately described?	(x)	( )	( )	( )
Are the results clearly presented?	( )	(x)	( )	( )
Are the conclusions supported by the results?	(x)	( )	( )	( )

Comments and Suggestions for Authors

We have added some more facts regarding the background and more references.

Thank you for the opportunity to review a manuscript entitled: "POLYCHLORINATED BIPHENYLS IN THE SNOW COVER OF SOUTH-EASTERN KAZAKHSTAN." 

The topic of the manuscript is of interest and novel. The results are interesting and well described. However, there are a few things that should be improved before publication. My detailed comments are presented below: 

1. The introduction is well written and adequately describes the selected regions and the risks imposed by PCBs; however, some of the literature there is quite old and could be updated.

You are right! Even in Central Asia, including Kazakhstan there is a limited number of research publications on the subject, and they are more old as new references. However, all of which were found in the public domain are cited in this manuscript. We have tried to find some new references and have added them.

2. Please fix the headings in the materials and methods to fit with the journal guidelines. 

Thank you: You are right! We have relasised the necessary changes of the headings according to the guiedlines (subheadings italic or cursive) 

 

Figure 1 is not necessary, especially in a non-English language. Perhaps the authors should consider moving it into supplementary data. Other than that, the methodology is adequately described.

 Thank you for your advice! We will put it into supplements (Suppl. 1).

3. Results: The description of the results is nicely written and contains many details. However, the figures could be improved. Since the journal publishes in electronic form, could the authors present the data in figures 3 & 4 in color? Either comparing changes between years in the same point by using different colors or gradients the severity of the problem? 

Thank you! You are right! We have realised improvements according to your proposals.

4. The same comment for figure 5 - this map is crucial and could also be referenced in the methodology section. Perhaps the authors could mark different points with different colors and then use the same colors for the graphs for the exact location? For example: if I'm interested in Big Almaty Lake and it has a green color on the map, I'm looking for green bars in the results graphs. I think the manuscript would greatly benefit from it when it comes to its readability. 

Thank you also for these advices! We have improved Fig. 5 too.

The writing part of both the results and discussion section is proper and well proofread. 

 

Submission Date

11 July 2022

Date of this review

02 Aug 2022 11:23:35

 

Revision: 8th and 15th August 2022

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Accept in this form.

Reviewer 3 Report

Thank you for the opportunity to review the revised version of this manuscript. The authors significantly improved the manuscript since the first round of reviews and answered all of my questions. No further comments.