A Comprehensive Analysis of Agricultural Non-Point Source Pollution in China: Current Status, Risk Assessment and Management Strategies

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This study provides a comprehensive analysis of agricultural non-point source pollution in China, focusing on the current status, risk assessment, and management strategies.

1) Regarding lines 90-91, could you please clarify the rationale behind selecting PE, PP, PA, PET, and PS? Is agricultural film comprised of only one of these types, or does it include all mentioned types?

2) On lines 97-98, the choice of reference value raises a question. Given the significant nationwide variation in Mps abundance, could you elaborate on why this particular reference value was chosen?

3) For lines 231-233, it might be beneficial to consider including more recent publications for reference. For instance, Xiao, S., Cui, Y., Brahney, J., Mahowald, N. M., & Li, Q. (2023). Long-distance atmospheric transport of microplastic fibres influenced by their shapes. Nature Geoscience, 16(10), 863-870.

4) Concerning line 330, if the microplastics discussed are solely derived from agricultural film, it may enhance clarity to specify this in the section title.

5) On line 342, could you provide further details on the methodology used to conclude that the microplastics in question are classified as Class II in terms of ecological risk?

6) Regarding Table 2, it appears that the underlying provincial data, which should inform the calculations according to equations 1-4, is not present. If this is the case, including this data could significantly strengthen the analysis.

I hope these suggestions are helpful for refining your manuscript. Your research contributes important insights into the field of environmental science, and I look forward to seeing the final version of your study.

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

The paper is clear and fluent while presenting specific technical elements. The objectives of the research are explained and so is the methodology. Regarding the latter, it is the construction of indices, so the paper presents results that are in the descriptive statistics. I suggest expanding the discussion and recommendations.

Regarding table 1, 2, and 3 please insert legend with variable meanings (TN, TP, PLI, H, RI respectively). Better, emphasize the source of the data and describe more about the processing. 

Author Response

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Reviewer 3 Report

Comments and Suggestions for Authors

The study mainly concerns water pollution. This should have been clear from the title.

On line 31: it would also be necessary to explain what "NPS" means when it first appears in the text.

Line 67: China has only 17.72% of the world's population and is 2nd after India, which has 17.76% of the world's population.  https://www.worldometers.info/world-population/population-by-country/

L 138: Tables S6-S8 do not provide details about the source of the data and the years in which the data were taken

Also, the figures and tables in the paper do not sufficiently explain what the presented values represent.

Author Response

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Author Response File: Author Response.docx

Reviewer 4 Report

Comments and Suggestions for Authors

The manuscript is well written and organized, showing the concern and raising general aspects about agricultural non point sources of pollution (AGNPS) in China. However, the text and general presentation of the study leave open some gaps that need to be better filled.

At the end of the introduction, as well as in the methodology and remainder of the manuscript, the issue of microplastics is highlighted.

1 - Regarding this aspect, authors are requested to present a description of the relationship between microplastics and agricultural sources or pollution, as nothing about this pollutant was commented in the introduction. I suggest a paragraph to describe the relationship between agriculture and the degradation of plastic films.

2 – In item 2.2.4 it is necessary to make clear the meaning of each element of the formulas presented. Table S4 does not present them all.

3 – In the results, item 4.1 does not present risk assessment data, but its only on nitrogen and phosphorus concentrations in water, therefore the topic title (L. 300) must be modified.

4 – In the results, 4.2 reports on the ecological risk index and highlights that it is based on the toxicity of the compounds (L. 338). For which organisms is this toxicity measured? Complete the sentence with this information.

5 – In all topics of discussion, the Ecological Risk Assessment of the detected substances is presented, but in the title and in other points of the text the term Risk Assessment is mentioned. Make it clear at all points in the manuscript that the study carried out was on Ecological Risk Assessment, as Risk Assessment is a term most used to present data relating to the risk to human health.

6 – The study places great emphasis on non-point pollution from agriculture. But how can we confirm that all the points presented are only affected by AGNPS and not by specific urban sources of pollution? How can we ensure that the sources of pollution come exclusively from agriculture? This aspect should be better described in the methodology.

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

Thanks for improving the manuscript.

Reviewer 4 Report

Comments and Suggestions for Authors

The authors answered all questions and the manuscript can be accepted in its current form.