State of Knowledge on the Effects of Tire-Derived Aggregate (TDA) Used in Civil Engineering Projects on the Surrounding Aquatic Environment
Round 1
Reviewer 1 Report
See attached file.
Comments for author File: 
Comments.pdf
Author Response
The paper briefly mentions that the amount of synthetic organic chemicals (SOCs) leached from TDA into water samples may vary depending on experimental conditions, but fails to provide a comprehensive analysis of these conditions.
The text in 6.3 was revised as follows: The amount of SOCs that leach from TDA into water samples may vary depending on the test conditions, such as exposure time, presence of headspace, organic carbon content in water, sample collection method, etc.
• A lack of in-depth discussion on the factors influencing leaching, such as pH variations, moisture levels, and temperature changes, and how real-world scenarios might impact the leaching behavior of TDA.
The section '5.5. Factors Affecting TDA-Component Leaching' discussed the major factors influencing leaching.
• The paper overlooks a critical aspect of TDA's sustainability as a fill material.
This paper was not intended to discuss the sustainability of TDA, but mentioned in Abstract, Introduction, and Section 2.1, nine times.
• While the study highlights the favorable aspects of TDA, it could benefit from a brief mention of any potential limitations or challenges associated with its use, providing a more balanced perspective on the topic. This would help readers anticipate potential areas of concern or further research.
Section '6.5 Gaps in Knowledge' covers potential limitations and challenges.
• Given the potential for exposure through water sources or direct contact, a more detailed exploration of the pathways through which humans might come into contact with these leached substances, along with a critical assessment of associated health risks, is necessary for a comprehensive evaluation of TDA's viability in civil engineering projects.
The following paragraph was added in Section 6.4. The pathways of leached chemicals from TDA used in civil engineering projects to humans are (1) dermal contact, (2) inhalation of volatilized chemicals, and (3) ingestion of contaminated drinking water consumption. Since (1) and (2) are highly unlikely, and prior studies showed the levels of leached chemicals were below regulatory limits, it can be said that the potential health effects of exposure to leached chemicals from TDA used in civil engineering projects are negligible.
Reviewer 2 Report
Jae K. Park, Isabella G. DeNooyer and Jack H. Wahl, “State of Knowledge on the Effects of Tire-Derived Aggregate (TDA) Used in Civil Engineering Projects on the Surrounding Aquatic Environment”, this article is devoted to collecting the most up-to-date scientific data on the environmental impact of recycled tires and specifically evaluating this data for use in TDA systems in civil engineering and environmental protection. The results of the review look impressive. However, I recommended supplementing the article. It seems important to mention in the introduction about recycling methods of tires (for example, https://doi.org/10.3390/ma13030782, https://doi.org/10.3390/polym13152494, https://doi.org/10.1016/j.susmat.2019.e00125). In some tables, commas are used to separate them, please bring them to the same format.
Minor editing of English language required
Author Response
The recommended papers by Fazli, A.; Rodrigue, D. Waste Rubber Recycling: A Review on the Evolution and Properties of Thermoplastic Elastomers. Materials 2020, 13, 782. https://doi.org/10.3390/ma13030782, Yerezhep, D.; Tychengulova, A.; Sokolov, D.; Aldiyarov, A. A Multifaceted Approach for Cryogenic Waste Tire Recycling. Polymers 2021, 13, 2494. https://doi.org/10.3390/polym13152494, and C. Sathiskumar, S. Karthikeyan,
Recycling of waste tires and its energy storage application of by-products –a review, Sustainable Materials and Technologies, 22, 2019, https://doi.org/10.1016/j.susmat.2019.e00125
do not seem to fit the paper since the paper focuses on the leached chemical from 'TDA.' Due to the length of the paper, the editor advised me to reduce the length. I hope the reviewer understands the limit of the paper to TDA only.
Table formats were corrected by the publisher.
Thanks for the review. I will include various usages and transformations of rubber materials for beneficial applications in future studies.
Reviewer 3 Report
In this manuscript, "State of Knowledge on the Effects of Tire-Derived Aggregate (TDA) Used in Civil Engineering Projects on the Surrounding Aquatic Environment”, the whole quality is not high. The discusstion is not deep and clear. So it is not recommended to be accepted.
Extensive editing of English language required
Author Response
This study was supported and approved by the U.S. Tires Manufacturers Association, Tire and Rubber Association of Canada, First State Tire Recycling, and Liberty Tire Recycling Company as part of the study, 'State of Knowledge on Tire Derived Aggregate.' Thanks for the review. I wish more concrete and constructive suggestions were made to improve the paper.
Round 2
Reviewer 1 Report
The revised manuscript titled "Assessing the Environmental Impact of Tire-Derived Aggregate (TDA) in Civil Engineering Projects on Aquatic Ecosystems" has been resubmitted by the authors. Its primary objective is to gather the latest scientific information regarding the ecological consequences of discarded tires and to assess this data within the context of TDA usage in civil and environmental engineering. The authors have incorporated changes into the manuscript based on suggestions from the reviewer.
Author Response
Reviewer's comment: The authors have incorporated changes into the manuscript based on suggestions from the reviewer.
No action is needed.
Reviewer 3 Report
Review comments on sustainability-2548861
In this work, the most up-to-date scientific data was collected on the environmental impact of scrap tires and the data were evaluated specifically for TDA applications in civil and environmental engineering applications. This manuscript will be considered for acceptable after revised based on the following comments:
1. Abstract must be enriched via valuable results which pave the way for understanding the audiences.
2. Why this review is needed?
3. Written is very week. In its current state, the level of English throughout the manuscript needs language polishing. Please check the manuscript and refine the language carefully.
4. The introduction section is very short and poorly described. It doesn't present the reference to the manuscript scope. In the introduction section, Authors should make an in-depth literature review concerning the application of advanced materials, structures, and composites for improving human life, environmental remediation and degradation of pollutants. Introduction has deficiency citation to valuable works published before. The following references are recommended to be cited, to improve the introduction section:
Composites Part B 174 (2019) 106930; Ultrasonics Sonochemistry 82 (2022) 105892; RSC Adv., 2021, 11, 40100–40111
5. The novelty of this study should be inserted in the text clearly
6. Results and discussion: - To increase the scientific value of the manuscript Authors should consider extension of the all results section with comparison of obtained results with the results described in previous publications.
7. How does your paper contribute to the advancement of knowledge?
8. What are the gap areas and the new contribution in the paper?
9. The authors should prepare all figures with better resolution.
10. The authors should prepare all tables with better quality.
11. Conclusion is not focused.
12. This work should be compared with the other work in Table form.
13. Indeed, there are impressive amount of results. However, the conclusions section needs to improve with selected and highlighted main findings.
14. The discussion is still poor and should be improved.
15. Where is the practical application of this manuscript? It must be added.
Extensive editing of English language required
Author Response
Thanks for your review. Please note the objectives of the study, which don't include the use of TDA and tire rubber for producing other polymers. This study is entirely focused on the environmental issues of TDA.
- Abstract must be enriched via valuable results which pave the way for understanding the audiences.
Following is the valuable result: TDA does not release a significant amount of potentially toxic compounds, the leaching rate in surrounding water environments is manageable, and TDA can even be a medium to remove nutrients and toxic organic and inorganic compounds commonly found in agricultural land and urban runoff.
- Why this review is needed?
In the abstract, see, “Unfortunately, the environmental suitability of TDA use has previously been questioned.”
- Written is very week. In its current state, the level of English throughout the manuscript needs language polishing. Please check the manuscript and refine the language carefully.
The paper was written by two native speakers and the firstauthor wrote over 100 papers in 40 years. The manuscript was revised further.
- The introduction section is very short and poorly described. It doesn't present the reference to the manuscript scope. In the introduction section, Authors should make an in-depth literature review concerning the application of advanced materials, structures, and composites for improving human life, environmental remediation and degradation of pollutants. Introduction has deficiency citation to valuable works published before. The following references are recommended to be cited, to improve the introduction section:
Composites Part B 174 (2019) 106930; Ultrasonics Sonochemistry 82 (2022) 105892; RSC Adv., 2021, 11, 40100–40111
Thanks for the recommendation. The main objective of this paper is to document the most up-to-date knowledge in the effects of TDA on the surrounding aquatic environment. Furthermore, due to the length of the paper, application of advanced materials recommended is beyond the scope of the manuscript. Note the title of the manuscript. There is no room for different recycling methods of TDA and advanced materials in this manuscript.
- The novelty of this study should be inserted in the text clearly.
The novelty is to document that TDA is safe when used in civil and environmental engineering applications. Currently, this topic has been reported in various papers and reports but not all in one paper.
- Results and discussion: - To increase the scientific value of the manuscript Authors should consider extension of the all results section with comparison of obtained results with the results described in previous publications.
Again, this is not a research paper. This is a state of knowledge review paper.
- How does your paper contribute to the advancement of knowledge? The tire industry asked us to document the most sensitive and important issue on the environmental impact of TDA.
This manuscript is a response to the tire industry’s request.
- What are the gap areas and the new contribution in the paper?
Again, the contribution is meeting the demand of the tire industry and the gap in knowledge is summarized in the conclusion section.
- The authors should prepare all figures with better resolution.
Sorry about the poor quality of the figures but the journal accepted them.
- The authors should prepare all tables with better quality.
The journal didn’t request any request for better quality of the tables.
- Conclusion is not focused.
The conclusions were based on the tire industry’s specific requests. We cannot understand why the conclusion is not focused. Note that conclusions are unusually longer than research papers. Note that the conclusions are long because we need to cover important issues related to TDA.
- This work should be compared with the other work in Table form.
We initially wanted to have a table format. Unfortunately, due to the different experimental conditions with different tire materials, it was more confusing. Thus, we decided not to use a table format.
- Indeed, there are impressive amount of results. However, the conclusions section needs to improve with selected and highlighted main findings.
Please be more specific. The conclusions section was reviewed by more than 10 people in the tire industry and the reviewers hired by the tire industry for our study.
- The discussion is still poor and should be improved.
Which part of the discussions do you talk about?
- Where is the practical application of this manuscript? It must be added.
The conclusions are practical applications when tire recyclers promote the use of TDA. Again, the paper has been reviewed by over 10 people in the area of TDA application and recycling, along with the U.S. and Canada Tire Manufacturers Associations.
The English native speakers, the second and third authors, reviewed the paper. Refer to the modifications made in the manuscript. Apparently, the reviewer doesn't look like a native English speaker. I found a few mistakes even in the review questions.
Round 3
Reviewer 3 Report
The authors make moderate revisions to the manuscript, and give a relevant response to the issues the reviewers concerned. Therefore, it could be considered as potential publication.
