Microplastic Contamination of Three Commonly Consumed Seafood Species from Taiwan: A Pilot Study

Round 1

Reviewer 1 Report

 A very nice work. Congratulations! 

Author Response

Thank you very much for your positive review.

Reviewer 2 Report

The manuscript   entitled    Microplastic Contamination of Three Commonly Consumed Seafood Species from Taiwan: a Pilot Study  is an interesting study dealing with the presence of microplastics in seafood commonly consumed by Taiwanese people .

The manuscript be Accepted  after minor revision .  Text editing for moderate English changes are required .

For example :

The use of the word we  along the text is not suitable

Abstract

-    We therefore present a pilot study  .. A pilot study  of microplastic contamination of seafood products commonly consumed by Taiwanese people was presented .

-  We examined six batches  :   Six batches of three seafood species  were examined   for the presence of microplastics using FTIR spectroscopy.

• we estimate that     A few thousand microplastic particles are estimated  to be annually consumed on average.

Introduction :

-  Possible human health impacts of microplastic and nanoplastic pollution are the possibility of internal injury and toxic reactions after ingestion or the indirect contamination of air, food, and water with harmful substances (see Discussion).

Materials :

- Briefly, we prepared   clean, microplastic-free water using a vacuum pump and filter system was prepared , and then used the clean water to produce the 10% KOH solution.

- After defrosting, we unwrapped the sample    the samples were unwrapped  and placed it immediately into a new vial which was then filled with the KOH solution in a clean laboratory environment.

- We then used   Then the same vacuum pump and filter system  were used to filter each vial’s contents separately through a filter paper with a 20-25 μm pore size (Whatman Laboratory Products) which took less than one minute.

-Besides using filtered water and aluminum caps, we further minimized    contamination of samples was minimized by always wearing a laboratory suit which does not shed fibers [32].

-During the laboratory work which we described above, we also always conducted three controls:

1. Blank run: We filled vials vials were filled with the KOH solution and subjected them to the same procedure as above, but without animal samples in them, and then filtered the solution through a new filter paper.

Author Response

Author's Notes to Reviewer

The manuscript be Accepted after minor revision. Text editing for moderate English changes are required.

For example:

The use of the word we along the text is not suitable

Abstract

-    We therefore present a pilot study  .. A pilot study  of microplastic contamination of seafood products commonly consumed by Taiwanese people was presented .

-  We examined six batches  :   Six batches of three seafood species  were examined   for the presence of microplastics using FTIR spectroscopy.

• we estimate thatA few thousand microplastic particles are estimated  to be annually consumed on average.

Our response: Thank you for the suggestion. We substituted the “we” against the suggestions made by this reviewer.

Introduction :

-  Possible human health impacts of microplastic and nanoplastic pollution are the possibility of internal injury and toxic reactions after ingestion or the indirect contamination of air, food, and water with harmful substances (see Discussion).

Our response: We deleted it.

Materials :

- Briefly, we prepared   clean, microplastic-free water using a vacuum pump and filter system was prepared , and then used the clean water to produce the 10% KOH solution.

Our response: Changed.

- After defrosting, we unwrapped the sample    the samples were unwrapped  and placed it immediately into a new vial which was then filled with the KOH solution in a clean laboratory environment.

Our response: Changed.

- We then used   Then the same vacuum pump and filter system  were used to filter each vial’s contents separately through a filter paper with a 20-25 μm pore size (Whatman Laboratory Products) which took less than one minute.

Our response: Changed.

-Besides using filtered water and aluminum caps, we further minimized    contamination of samples was minimized by always wearing a laboratory suit which does not shed fibers [32].

Our response: Changed.

-During the laboratory work which we described above, we also always conducted three controls:

1. Blank run: We filled vials vials were filled with the KOH solution and subjected them to the same procedure as above, but without animal samples in them, and then filtered the solution through a new filter paper.

Our response: Changed.

Reviewer 3 Report

INTRODUCTION

"although different thresholds have been used by various authors [13]."

Please cite various references. 

"Microplastics have already been found in various human foods: beer, drinking water, honey, seafood, sugar, and table salt [14-16]."

Do not cite only table salt papers. Choose one of the table salt studies and add other studies dealing with other kinds of food items.

Here some recommendations: 

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0194970

https://www.mdpi.com/2071-1050/12/14/5514

https://www.sciencedirect.com/science/article/pii/S2212429220310531

MATERIALS AND METHODS

"and it has the 30th highest GDP per capita income in the world, with people consuming much local food, but also food imported from all over the world." 

unnecessary details for this study.

"which were randomly chosen from the list of commonly consumed species"

What kind of random selection procedure was applied.

Did the authors filter solutions used for digestion?

Any chosen matching score for the library match?

What kind of random selection procedure was applied for the selection of particles for FTIR analysis?

RESULTS

In the Materials and Methods section, you mentioned that you analyzed 65 particles out of 100 particles but in the results section the total number of chemically identified particles was reported as 100? How could it be possible? If you analyzed 65 particles and then you can only say sth about 65 particles. You cannot generalize it. Please clarify it!!

DISCUSSION

Please avoid the cite media news!!

Author Response

Dear Editor,

As far as I could see, only a few grammatical changes were necessary, which we all accepted. We furthermore responded to the suggestions below. Please let me know if any further changes are needed.

With my best regards, Bruno Walther

The submitted manuscript has been improved since the last submission. However, the papers need some minor questions.

1. Table 3.

1.1 Please verify the superscript letters "d Calculation is presented in the Results."

Our response: done.

1.2 I think that "Total no.a" column is wrong because Total no.a is a summary (62+6+15+10+2+5 = 100) and not a mean value like No. per kg. Please, improve this. Maybe mean + SD could be useful. In this case, I think that the following sentence "The mean number of microplastics kg-1 across the three species was ((116.7 + 107.9 + 39.0) particles kg-1)/3 = 87.9 microplastics kg-1 of fresh seafood" should be removed from the manuscript. It's the same information in the table.

Our response: Yes, the information in the bottom row of the Table could be improved, so we did that. I hesitate to remove the sentence because showing the actual calculation removes any ambiguity about how the final mean number was reached (because the mean could also be calculated across the six batches instead). Therefore, I consider this sentence essential information in order to be crystal-clear.

1.3 After changes in the manuscript, I think that the table S2 is not needed because abbreviations are given in Table 3.

Our response: We continue to consider Table S2 useful because it also contains some references and explanations which make understanding the classification of the polymers easier. Furthermore, this table is ONLY in the supplement where it hardly interferes with the brevity of the main manuscript.

1.4. I think that abbreviations should be reviewed (both in table and results section). I think that abbreviation for "poly(ethylene–propylene–diene)" is EPDM and not PE-PP. See for example https://doi.org/10.1002/app.33359 or https://doi.org/10.1177%2F0095244316653262

Our response: Done.

2. I saw that poly(ethylene–propylene–diene) is a type of synthetic rubber, and it's the second polymer type most important in the submitted manuscript. Still, this polymer is not discussed. Why? Maybe this source can be related to Conveyor belts from fishing ships or sorting plants. Is it possible?

Our response: We added the following sentence: “Likewise, EPDM is a type of synthetic rubber which could possibly originate from conveyor belts during processing (e.g., https://www.exxonmobilchemical.com/en/solutions-by-industry/industrial-applications/conveyor-belts).”

Please, try to improve this information and try to improve the discussion section.

Some examples:

https://doi.org/10.1016/j.chemosphere.2020.128554

https://doi.org/10.1016/j.scitotenv.2020.136826

https://doi.org/10.1016/j.marpolbul.2019.110672

https://doi.org/10.1016/j.envpol.2018.11.091

https://doi.org/10.1016/j.marpolbul.2020.111553

Our response: Sorry, we do not understand these recommendations because they are too general and lack sufficient detail to be followed. Please provide much more extensive detail about what information needs to be changed and where and how and why. We are happy with the Discussion as it is now.

Author Response File: Author Response.pdf