Dry and Wet Deposition Fluxes and Source of Atmospheric Mercury in the Forest in Southeast China

Round 1

Reviewer 1 Report

The article is of scientific interest, since it describes the study of the flows of a substance of the first hazard class – mercury in the forest ecosystem in China. The authors apply an original approach, capturing the precipitation of mercury with precipitation and in dry form for almost a year, that is, they cover all seasons. Note that such studies are relatively rare in world practice, and for China, I am sure, this was done for the first time, that is, it is unique.

Nevertheless, after reading the article, there are still questions, answering which the authors will certainly improve the perception of information and remove doubts from readers.

So, in the abstract, the authors briefly describe the results of the study, but do not say that the concentrations of Mg, Ca, Cd, Cu, Zn, Pb, Cr were also studied - and then it sounds in the introduction, the materials and methods mention only how they were determined, and only correlations in the results. Perhaps it is necessary to briefly describe the results for these elements so that the picture is more complete.

Further, it is not completely clear exactly how dry deposition was determined. It is clear from the methods that wet deposition was determined in a small amount of precipitation and subsequently multiplied by the total amount of precipitation, and dry deposition was not considered directly in suspension? The suspension was diluted and then the recalculation took place? Since these are materials and methods, it is good if there is clarity here. Also, from the reader's point of view, I think it would be useful to post a photo of the sampler device and the location of the station in the forest.

It makes sense to describe the natural area where the observation station is located. The mountain itself has what height, and at what height the station is located, the nature of the forest (it is indicated only that it is a subtropical forest). To highlight your research, indicate its uniqueness – you can describe the landscape in more detail – which species of trees, shrubs prevail, which soils, fauna, whether there are protected red Book species of plants and animals. Yes, there is a map, but it does not provide a complete picture. It is also important to understand what types of industrial or agricultural production are carried out in the neighborhood, since the authors talk about anthropogenic influence. I consider it necessary to briefly give an economic description of the surrounding areas (as potential suppliers of mercury to the environment).

Figure 1. It may be useful to supplement by specifying the location (name of the area)

Figure 3. Mercury in dry deposition is almost everywhere higher than in wet.

Figure 4. According to this figure, it turns out that wet deposition of mercury prevails over dry.

Is there a discrepancy here, or do I understand it badly? It is unclear why this is so.

 

Conclusions. Here it is necessary to give answers to the questions posed in the introduction, as well as to indicate whether the purpose of the study has been achieved, how the tasks have been solved, and what prospects. I think that the conclusions can be improved by reflecting all these points.

The research is very interesting, it corresponds to the direction of the journal, however, from my point of view, it needs to be finalized.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

I have reviewed the manuscript entitled " Dry and wet deposition fluxes and source of atmospheric mercury in the forest in southeast China ". The authors how Hg deposition in the forest system of southeast China. The paper is concise and generally well written.

I only have minor comments as below.

The authors should indicate the replicates number in the caption of all the figures.

Fig2: The authors should add a regression line to indicate the trend of the Hg concentration over the past years.

Fig 3 and 4: authors should add standard error bars in the bar plots.

Table2: add a replicate number

Figure 5 and 6: since the authors’ analysis focus on the correlation, please add the correlation figures of flux and precipitation in the supplement figures.

Author Response

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Reviewer 3 Report

The authors must seek the help of a scientific editor to help them produce a viable manuscript for publication. In addition, there is a need to provide a more nuanced introduction and justification of the study, with clear objectives.  The materials and methods are sketchy and do not meet the normal standards of repeatability i.e., providing such detail and clarity that other researchers can repeat the study and validate the results of this study or otherwise.  The presentation of the results and their discussion are similarly obtuse and require major revision

Author Response

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Reviewer 4 Report

I reviewed the research article “Dry and wet deposition fluxes and source of atmospheric mercury in the forest in Southeast China”, which is an interesting research work. I would like to accept this article after the following suggestions:

In the abstract part the authors should introduce the study implication. Some of the statements in the introduction needed citation to support, authors should provide a rationale of the study site selection, is this due to the high risk due to Mercury contamination or source?

In the data methodology section details needed, i.e. the source of the equation 2, deposition flux, many authors including “Huang, J. and Gustin, M. S.: Use of passive sampling methods and models to understand sources of mercury deposition to high elevation sites in the Western United States, Environ. Sci. Technol., 49, 432–441, https://doi.org/10.1021/es502836w, 2015a, “used this equation in their study. How different is equation compared to the other studies? In the result section quality of the figure 2 needs improvement, in current form its hard to follow.

Table1, some of the studies cited are too old, that needs to be replaced with more recent studies on the issue, like Engle et al 2015.

The limitations of the study also need mentioning in the discussion/conclusion section, for example why lowest concentration was observed in June, link this to the rainfall abundance and frequency, and prevailing air.

Overall, an interesting research work, I would like to accept this article after the above suggestions.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Accepted as it stands