Significant Fragmentation of Disposable Surgical Masks—Enormous Source for Problematic Micro/Nanoplastics Pollution in the Environment

Round 1

Reviewer 1 Report

Authors conclude that it is DSM pose an extremely hazardous risk, but the harmfulness of nanoplastics is still being debated scientifically, and we believe that consideration should be given to the wording.

A description of the DSM sampling methods, sample details, staining, representativeness, etc. is needed.

Author Response

Response Reviewer 1

Journal: Sustainability

Manuscript ID: sustainability-1836802

Title: Significant fragmentation of disposable surgical masks – enormous source for problematic micro/nanoplastics pollution in the environment

Authors: Alen Erjavec *, Olivija Plohl, Lidija Fras Zemljič, Julija Volmajer Valh

Type of manuscript: Article

Dear Reviewer 1,

Thank you for reviewing our paper and for your comments. We have revised the manuscript according to the proposed suggestions. We are most thankful for all the comments and proposals. Please find enclosed the revised version of our manuscript. We hope the revised version is now suitable for publication in Sustainability and look forward to hearing from you.

Authors conclude that it is DSM poses an extremely hazardous risk, but the harmfulness of nanoplastics is still being debated scientifically, and we believe that consideration should be given to the wording.

A description of the DSM sampling methods, sample details, staining, representativeness, etc. is needed.

Answer:

We paraphrase extremely hazardous risk into potentially hazardous risk in the text of the manuscript.

Description of the DSM sampling methods was added to chapter 2.1 Sampling and gravimetric analysis:

The waste DSM sample was collected in a collection campaign on the Faculty of the Mechanical Engineering University of Maribor. In the campaign were participating students, professors, and staff employed on the faculty who were regularly delivering spent DSM. During the campaign over 10.000 spent DSMs were collected. A sampling of the whole collected sample was carried out according to standard SIST TP CEN/TR 15310-4:2007 to collect a representative sample for further analysis. Particular caution was given when collecting and sampling, due to the potential infectiveness of the material.

Reviewer 2 Report

The study aimed explore the fragmentation of disposable surgical masks in the environment. The data includes characterization of physicochemical properties of various components of masks such as weight loss, degree of aging, size changes, and leached substances. Overall, the study is very interesting and has broad applications for microplastic research especially at Covid-19 period.

Minor Comments:

1)      The authors should provide information about number of MPs from mask under artificial weathering processes.

2)      Fig.6(b) should provide EDS to confirm these particles is from mask (carbon-dominant).

3)      When use “significant” or “significantly”, please provide statistical analysis.

4)      Fig. 5: scale bars are not clear.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

In this work, the disposable surgical mask (DSM) was evaluated. The Xenon test and Toxicity characteristic leaching procedure (TCLP) were performed to study the changes of DSM. The authors did not quantify the amount of microplastics released, nor did they analyze the data in depth. As such, the work appears to lack depth and appeal. Moreover, in the Introduction and Results parts, the contents are not concise enough and lack good logic. In the drawing of figures, a larger improvement is also required. So based on the above reasons, this paper is suggested to major revision. Finally, some questions and errors are listed in the following.

Questions & Errors:

1. Line 22-23: “the Xenon test and Toxicity characteristic leaching procedure were used for the first time to analyse and evaluate the leaching of micro/nanoplastics.” During the period of your submission, a large number of studies on the risks of microplastics brought by masks were still published, and these research methods and concerns became more systematic and in-depth, so it is recommended not to describe it here as “for the first time to analyse”.

2. The part of Introduction need to be improved. The content of the description is not concise enough and does not reflect good logic. We suggest that the author analyzes the research gap and the innovations of this work completely, and then talk about how to conduct this research and what goals can be achieved.

3. In Fig. 5, the scale on the photo is not clear.

4. In Fig. 7(b), the ordinate should be the percent of weight change, not weight loss. Based on this, the corresponding description of Fig. 7(b) in the text should also be modified (Line 419-421).

5. The title of Fig. 8 is wrong, please change “before and after filtration” to “before and after xenotest”.

6. Line 194-195: “The samples were then dried at 90 ° C for 1 194 hour to maintain a constant mass.” Why choose a temperature of 90 ° to dry plastic products? At this temperature, some plastic products will deteriorate.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 4 Report

The research paper sustainability-1836802 entitled “Significant fragmentation of disposable surgical masks source for problematic micro/nanoplastics pollution in the environment." is attractive, easy to read, and its contents are interdisciplinary. However, major revisions must be conducted before its acceptance. Here are some specific comments:

1. I have some concerns about the Toxicity Characteristic Leaching Procedure (TCLP) methodology employed by the authors. For example, cutting the face mask samples (layer samples from face masks around 1 cm²) may damage the integrity of each mask layer, which could affect the results over the number of MPs obtained during the TCLP experiment.

2.  The temperature to dry the face mask samples is very high (C° 90) and can affect some polymers' properties and glass transition temperature. 

4. 

1. The authors filtered all analytical solutions and distilled water before use?. Improve Quality assurance (QA) and quality control (QC) of the manuscript.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

I think the manuscript can be accpeted now.