Trifolium pratense and the Heavy Metal Content in Various Urban Areas

Round 1

Reviewer 1 Report

Detailed comments

Abstract

In my opinion, the presentation of heavy metal content ranges in the Abstract is inappropriate. I suggest deleting this data. I propose to describe the calculated factors (BCF, TF and CF) in this sentence.

Introduction section

Page 2. Line 59. I do not agree with this statement. After reviewing the literature on T. pratense and heavy metals, I find that this aspect has been studied by many authors. I suggest reviewing the literature on the subject, especially the articles suggested below.

Materials and Methods section

Fig. 1. I suggest marking the map of Poland in neutral colors, e.g. white, grey. The next map contains colors (including pink) indicating the type of land development.

Tab. 1

I suggest not using the capital 'P' in 'Park' as in the other descriptions.

Please give more detailed description of what 'near' means in: 'area near the lake' and 'area near the river'. How far from the shore was samples taken and analysed?

Tab. 2.

In Tab. 2, it is proposed to use only the symbols of sampling sites. They are described in Tab. 1.

In the Materials and Methods section does not describe of pH and Cond. analysis. Was the extract made in H2O or KCl for pH? In what proportions? Please give a pH-meter and conductometer details.

Table 3.

Tab. 3. Please check and improve the accuracy of HM content representation for soils, leaves and roots. Specifying values to three decimal places is inappropriate.

Page 5-6. Line 197-205. In the paragraph, are quoted the results presented in tab. 3. This is inappropriate. The values given in the table should not be quoted again. I propose to delete the data from sentences.

The same remark applies to paragraph: Page 6. Line 222-229 and section ‘3.3. Content of heavy metals in plant leaves’ (page 8).

Tab. 4. (Page 9, Line 292)

Please check the numbering of the table and correct it also in the text

Discussion section

Page 9. Line 295-300. The paragraph should be moved to the Introduction section. This paragraph should be removed from the Results Discussion.

Page 10. Line 318-320. The data are given in Tab. 4 (not adequately described as Tab. 2). They should not be rewritten in the discussion of the results.

General remark to discussion of the results

The discussion of the results is poor and needs improvement. It is not enough to state that an area has a high or low content of heavy metals. The reasons for this effect should be considered. The discussion of the results lacks a comparison with the results of more references.

Conclusions section

Conclusions should not be numbered. Please change it.

I disagree with the first statement. The authors have not proven that T. pratense can be an indicator. Determining only the relationship between the HM content in the plant and the soil is not sufficient.

Giving results (values) in conclusions is inappropriate. Please remove it.

Conclusions 3 and 4 do not add anything to the conducted research. I suggest giving the order of HM accumulation in plants, e.g. Pb>Cd>Cu etc.

The Conclusions section needs some serious improvement.

The obtained results  should be summarized in this section. In my opinion, the authors have not proven the possibility of using T. pratense as a bioindicator. The research was carried out once (in May) in a small area (one city). These are the results that can be taken into account in the assessment of soil and plant quality, carried out in environmental monitoring in this area.

References

In the references, the authors presented a wide range of articles related to the researched subject. Among these literature items, a large part are recent articles (up to 5 years old).

In my opinion, it is worth reviewing these articles on the study of heavy metal accumulation in T. pratense, e.g.

DOI: 10.12911/22998993/91884

DOI: 10.1016/j.jhazmat.2022.129128

DOI: 10.1016/j.envexbot.2021.104458

General remark

In my opinion the scientific value of the manuscript is weak. Therefore, I suggest improving the manuscript, especially the Discussion and Conclusions sections.

Author Response

Dear Reviewer,

Please see the attachment.

Regards,

Author Response File: Author Response.pdf

Reviewer 2 Report

The manuscript concerns an essential topic of ‘Trifolium pratense and the heavy metal content in
various urban areas. The research is interesting and has novelty. However, It has been seen that
the authors have dealt with the issues very quickly. Where need more focus on the manuscript
(Introduction part). And it needs major revised in this part of manuscript to reach the standard of
the journal. There are some points that should be addressed before the manuscript is suitable for
publication in ‘Sustainability’.
Q1 : Why the authors chose these heavy metals, and why they didn't use other polluted heavy
metals such as Ag and Ar or etc?
Q2: Why the authors chose Trifolium pratense L.
Line 12. Various human activities can be replaced with ‘’Anthropogenic activity’’
Line 26. The keywords can't be the same word as the title, please replace them.
The introduction is too short. The author needs to write 2-3 lines for each heavy metal mentioned
in this study. So what is the negative impact of those heavy metals on plants, the environment,
and the human body? Please describe. Another thing, there are no hypotheses in this study,
please mention this in the text.
The aim of this study is confusing; it needs to be rewritten again clearly.
The literature citation is insufficient. The authors need to use some recent references.
They are some references that authors can use them
Li, W., Shi, Y., Zhu, D., Wang, W., Liu, H., Li, J.,... Fu, S. (2021). Fine root biomass and
morphology in a temperate forest are influenced more by the nitrogen treatment approach than
the rate. Ecological indicators, 130, 108031. doi: 10.1016/j.ecolind.2021.108031.
Zhao, Z., Wang, P., Xiong, X., Wang, Y., Zhou, R., Tao, H.,... Xiong, Y. (2022). Environmental
risk of multi-year polythene film mulching and its green solution in arid irrigation region.
Journal of hazardous materials, 435, 128981. doi: 10.1016/j.jhazmat.2022.128981.
Wang, Z., Liu, X., Ni, S., Zhuang, X., & Lee, T. (2021). Nano zero-valent iron improves
anammox activity by promoting the activity of quorum sensing system. Water Research, 202,
117491. doi: https://doi.org/10.1016/j.watres.2021.117491.
Pan, C., Yang, K., Erhunmwunsee, F., Li, Y., Liu, M., Pan, S.,... Tian, J. (2023). Inhibitory effect
of cinnamaldehyde on Fusarium solani and its application in postharvest preservation of sweet
potato. Food Chemistry, 408, 135213. doi: https://doi.org/10.1016/j.foodchem.2022.135213
Line 139,140. Subscript and superscript
Line 142. Reference need it
Line 146. Reference need it
Line 184. variance (ANOVA); one way or two way?

Which post hoc test did the author use for this study? Please mention this in the text.
How many replicates for each treatment (samples)?
Results:
Line 195,206 : The mean difference letters (a, b, ...) need to show in the table 2,3

Author Response

Dear Reviewer,

Please see the attachment.

Regards,

Author Response File: Author Response.pdf

Reviewer 3 Report

The manuscript studies Trifolium pratense and its heavy metal concentrations in various urban areas as a bioindicator. The author carried out a systematic investigation in Poznan city of Poland. The topic is good. However, the research method is not clearly introduced, the experimental data need to be verified, and the data analysis also needs to be in-depth. A major revision must be made before it can be accepted for the journal.

The detail recommendations are as follows.

1.       In the first paragraph, the background on heavy metal pollution and hazards could be simplified.

2.       What are the requires for a plant acting as a bioindicator of heavy metal pollution? It should be made clear in the second paragraph.

3.       Line 57-67, what research has been carried out on Trifolium pratense L. acting as a possible bioindicator plant in Reference 2.

4.       Line 57-67, compared with Reference 2, what research is this article intended to expand?

5.       Line 69-70, the fist point of the aims is not the focus of this article.

6.       It is suggested to supplement the correlation analysis to reveal the relationship between the contents of heavy metals in soil, plant roots and leaves.

7.       Please add the sampling numbers for each sampling site in Table 2.

8.       Pay attention to the expression of units, unify the upper and lower scripts, and change the form of /min to min-1.

9.       Line 176, change the word accumulation as concentration or content.

10.    Use EC rather than Cond. in Table 2.

11.    The data in Table 2 is not very credible, because its accuracy is much greater than the accuracy that field sampling would have.

12.    The number of significant digits for the data in Table 3 is not recommended to exceed 4 digits.

13.    Line 292, it should be Table 3. The BAF in the table should be BCF.

14.    It is not necessary to give LCF or MCF in the table, however, the basis for judgment should be given in the manuscript.

Author Response

Dear Reviewer,

Please see the attachment.

Regards,

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Dear Authors,

after reading the revised version of the manuscript (ID: sustainability-2316310 ), in my opinion it has been properly corrected. The authors made many corrections to the manuscript, which increased its scientific value.

In my opinion, it is suitable for publication in Sustainability journal.

Author Response

Dear Reviewer,

Thank you for your valuable feedback on our manuscript. We are grateful for the time and effort you put into reviewing our submission. 

Best regards

Reviewer 2 Report

Can be accepted

Author Response

Dear Reviewer,

Thank you for your valuable feedback on our manuscript. We are grateful for the time and effort you put into reviewing our submission. 

Best regards

Reviewer 3 Report

The manuscript has been well revised and there are two minor corrections to make.

Line 155, what dose NKCl mean?

Line 249, mg kg-1, -1 is a superscript. It is better to use positive statements, “different letters (a, b, c) indicate means are significantly different (p < 0.05) in the same row according to the post-hoc Scheffé test.”

Line 389, there is an indentation for the first line.

Author Response

Dear Reviewer,

Thank you for your valuable feedback on our manuscript. We are grateful for the time and effort you put into reviewing our submission. 

We have improved the manuscript in the following way:

• Line 155 - the letter N was a mistake and has been removed,
• Line 249 - the superscript and the description has been improved,
• Line 389 - an indentation has been corrected.

Best regards