Biochar Extracts Can Modulate the Toxicity of Persistent Free Radicals in the Nematode Caenorhabditis elegans

Round 1

Reviewer 1 Report

Remarks to the Author:

Xuchao Zhang and colleagues explored the the potential toxicity of EPFRs on organisms as well as the modulating effect of DOM. The authors determined the neurobehavior and find that organic carbon leachable from biochars can modulate the toxicity of persistent free radicals in the nematode Caenorhabditis elegans. These data are very reasonable. But writing needs to be revised carefully.

Overall, I would support the publication of this study once the authors have addressed a series of changes.

My comments:

1. line 73：Add some references behind the sentence “neurobehavior including autonomic behavior (movement length, body bend, defecation interval) and sensory behavior (touch response and chemotaxis)”.

2. Add some description and relevant references about the selecting of C.elegans as the animal model for toxicity evaluation in introduction.

3. What is the OD value of OP50? Add it in the Material and method.

4. line 113 “Caenorhabditis elegans”, abbreviation “C. elegans” should be used here.

5. Why exposure the nematodes from L4 stage? Why were they exposed for 12h (line 162)?

6. The experiments of this manuscript are all based on exposure for 12h. What might be the effects of long-term exposure? Discuss it in the “Results and discussion”.

7. Why did you explore the neurotoxicity rather than other aspects of toxicity, such as reproductive toxicity?

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and suggestions for authors are presented in attachment

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

I have revised your manuscript entitled “Organic carbon leachable from biochars can modulate the toxicity of persistent free radicals in the nematode Caenorhabditis elegans” This is an interesting topic. But it needs some important changes. In select cases, poor grammar and/or word choice may lead to confusion and/or misconceptions. Some contradicting information in the data needs to be resolved, and the conclusions were also somewhat simplified. Units must be according to the International System of Units (SI) in the manuscript. Abbreviations and acronyms should be used consistently throughout the manuscript. Language and grammar should be carefully checked for readability.

·        Note: authors should insert the line and page numbers when they carry the corrections.

·        Title “Organic carbon leachable from biochars” modify to biochar extracts or biochar supernatants

·        Introduction is not sufficient

·        Line 52: “particulate matter” what the meaning of matter.

·        Line 60: Dissolved organic matter leaching from the biochar is low and it dependent on the feedstock type and pyrolysis temperature.

·        It is possible that the effect that you attribute is not to the organic matter, because biochar is rich in soluble minerals and nutrients.

·        Line 90: "biochar produced at 500 and 700 °C for 2 hours": From my long experience on biochar, the pyrolysis temperatures used to produce biochar in this study lead to the amount of dissolved organic matter being almost non-existent. Biochar produced at a temperature of less than 200-400 °C contains organic matter.

·        Authors should include a Table containing the main characteristics of unwashed biochar, washed biochar, and biochar supernatants such as free radicals, pH, electrical conductivity, alkali cations, and dissolved organic matter.

·        Line 100: μL or mL: Please unite the units

·        Line 103: “50 μL” How were these small quantities taken?

·        How was the determined dissolved organic matter in unwashed biochar, washed biochar, and biochar extracts? Mention the method used.

·        Line 113: “fractions” The expression is not accurate

Results and discussion

·        Line 189: The authors should mention the reasons for the phytotoxicity of biochar

·        Line 203: “three unwashed biochars” correct to “two unwashed biochars”

·        One of the most important problems of biochar is EPFRs

 

·        Rewrite the Conclusion

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

I have revised your manuscript entitled “Biochars extracts can modulate the toxicity of persistent free radicals in the nematode Caenorhabditis elegans”.