Research on the Closure and Remediation Processes of Mining Areas in Romania and Approaches to the Strategy for Heavy Metal Pollution Remediation

Round 1

Reviewer 1 Report

The manuscript is devoted to research on the status of closure and remediation processes of mining areas in Romania and to study of the degree of application of remediation techniques for water and soil pollution. These problems are undoubtedly relevant and attract the attention of researchers involved in various aspects of environmental science and sustainable development.

The manuscript makes a contradictory impression.

It begins with a rather extensive introduction, which could have been more concise and specific. It is desirable to conclude the introduction with a clear statement of the purpose of the article.

The ‘Study area’ section includes a description of several regions of Romania: Maramureș, Suceava, Harghita, Alba, Hunedoara and Caraș-Severin counties. The following are maps on which one can see the exploitation sites of metallic mineral substances for the selected areas at the level of the 1980s, 2000s and 2021. But in the next section 3.1 the authors consider only three objects (case studies), for which their location on the map is not even shown. It is not said why these objects were chosen for study.

The first сase study is associated with copper ore. There are two photos and a list of pollutants for this object. The second сase study is associated with barite ore processing,  and the main pollutants are also listed here, but there are no photos. There are photos for the third сase study, but there are no characteristics of waste, a list of pollutants, a source of pollution. This section does not contain any generalization on all three case studies and general conclusions.

The following sections do not contain any mention of these case studies or specific regions of Romania, listed in the ‘Study area’ section. At the end of the manuscript, the authors conclude that ‘the mining sector in Romania, although it has the necessary techniques and technologies for the ecological rehabilitation of degraded lands related to  the Extractive Waste Facilities and the elimination of negative impacts on the environment and public health, has not yet been able to fully concretize its remediation efforts’. But how does this common conclusion relate to the specific research objects mentioned earlier?

I would wish the authors to clearly define the purpose of the study, justify the choice of examples on which this study is conducted, provide more specific information for each object and formulate a conclusion based on the data presented.

 

Author Response

We would like to express our appreciation to the reviewer for the time and expertise provided toward the improvement of our paper. For the specific raised aspects, we offer the following arguments and revisions:   The introduction was re-structured. The last paragraph from the introduction details the content of the article and the prevailing conclusion.   The case studies are from those locations included in the maps, but their locations were not especially highlighted. In the last paragraph of the introduction, the reason for the selection of the respective case studies was made clear. The photos legends were amended to include details regarding the year and season of origin. Also, the text has been amended to include a concluding description of the environmental state as depicted in the photos.     There are not many scientific publications regarding the current state and the local environmental status for the over 500 mining operations declared closed. The conclusions have been amended to include the need for the implication of the larger scientifical community for further investigations and remediation efforts for these contaminated sites.   A different author described each of the presented case study so a text fragment related to a second study was unintentionally included. In fact, only two cases were intended to be detailed. The text has been corrected.

Reviewer 2 Report

The manuscript shows the information on the closure and remediation processes of mining areas in Romania. Such investigation are very important for practical application in order of environmental impact assesment and rehabilitation.

The authors provide an overview of a representative amount of literature sources (85 sources) and also mention the use of private information to achieve the purpose of the paper.

Nevertheless, the manuscript has a number of the following fundamental weaknesses:

1. Based on the results presented, the type of work should be labeled as a "review" rather than an "article".

2. In case the authors not only analyze data from previously published papers but also present their original results, it is necessary to add a "Materials and Methods" section to the paper.

3. Internal navigation through the text is broken. Figure 3 is referred to by the authors on page 15 (line 470), while Figure 7 is mentioned on page 13 (line 356). Moreover, figures 2, 4, 5 and 6 are basically not referenced in the text. 

4. Section 3 presents information about the objects considered, but neither at the end of the section, nor in the Conclusion section, there is no synthesis and logical analysis of the information. What exactly did the authors want to say?

5. Section 4 is labeled "Discussion." However, it is also more of an overview rather than a reasoned justification of the activities presented.

 

The manuscript submitted for review appears to be weak both in terms of content and presentation of results, as well as in terms of text design.

In its current form, in the opinion of the reviewer, the work cannot be accepted for publication.

Nevertheless, the authors can substantially revise the manuscript and resubmit it to the Editorial Board.

Author Response

We would like to express our appreciation to the reviewer for the time and expertise provided toward the improvement of our paper.

For the specific raised aspects, we offer the following arguments and revisions:

This is not an article focused on laboratory experimental research. The work is focused in presenting the context and current status of closed mining areas (mainly in respect to their greater environmental risks and effects) and to convey our opinions regarding the need to attract the public attention and a greater scientifical involvement to bring to light the actual local environmental state and encourage better ecological restoration for those closed mining activities which would be found lacking after an independent evaluation. The original data presented is constituted by the current status, presented through previously unpublished photos from the authors own fieldworks, of the selected case studies. The maps and tables were generated by us but are based on processed data from multiple sources.

The text was re-flowed to ensure a proper figure and table integration.

In the last paragraph of the introduction, the reason for the selection of the respective case studies was made clear. The photos legends were amended to include details regarding the year and season of origin. Also, the text has been amended to include a concluding description of the environmental state as depicted in the photos.

The Discussion section has been restructured to comprise the fragments from the introduction that better constitutes a discussion on the current legislative context and general statistical figures. This work did not comprise an actual experimental activity being more oriented toward data compilation and analysis with some case studies detailed based on the authors’ recent fieldwork.

The manuscript has been revised trying to answer to as many of the reviewers’ observations as possible. The authors hope that in its revised form the manuscript may be accepted for publication.

Author Response File: Author Response.pdf

Reviewer 3 Report

In this paper, Violeta-Monica Radu et al. examined the strategy for remediating heavy metal pollution in Romania. This paper holds great scientific significance, as the information it provides can make a substantial contribution to the field of environmental science. The paper is well-written, and I recommend its publication with a few minor modifications. Below are my suggestions.

Major concerns:

(1) The paper has a lengthy introduction. The authors might consider deleting approximately 20%-30% of the total words without altering the main ideas, if possible.

(2) The writing includes many short paragraphs, some of which consist of only one sentence. For instance, Line 39 reads, "The extraction of valuable mineral substances creates an imbalance in the natural environment, both in the extraction sites themselves and in the areas where the wastes resulting from the stages of exploitation and processing have been deposited [6-9]."

To the best of my knowledge, I recommend that each paragraph should contain around 5-7 sentences, with the first sentence stating the main point of the paragraph. The authors might consider combining some of the shorter paragraphs.

(3) Since this paper deals with heavy metals, it is suggested that the definition of heavy metals be provided. Here is an example (please refer to Figure 4):

[Link to Figure 4]

For example, while uranium ores are generally considered toxic materials, the authors should double-check whether uranium belongs to the category of heavy metals or not. The same applies to Au-Ag. Care should be taken when selecting the appropriate terminology.

Minor concerns:

(1) Figure 1, 2, 4: The authors may consider increasing the font size, especially for the text "active underground," "open cast mines," and "decanting ponds."

(2) Line 161: "Apuseni Mountains" is italicized. Line 169: "Apuseni Mountains" is not italicized. The authors may consider making the formatting consistent.

(3) Line 291: "Government Decisions regarding the process of mine closure and remediation." The authors may capitalize only the first word.

(4) Line 339, Figure 7: The authors provide six photos in one figure. I suggest that the authors label them as (a), (b), (c), (d), (e), and (f) and introduce them one by one, providing information about their location and year.

(5) Line 339: The authors may consider making Figure 7 bold, consistent with the formatting of other figures.

(6) Line 612 to 614: The author "V.-M.R." is hyphenated, while the other author's name is not. Please ensure consistency before publication.

I think the writing quality is good.

Author Response

We would like to express our appreciation to the reviewer for the time and expertise provided toward the improvement of our paper. For the specific raised aspects, we offer the following arguments and revisions:

The introduction has been restructured.

The text has been revised according to the observation.

A mention regarding the “heavy metals” designation was included in the introduction. Furthermore, the fact that Uranium and Au-Ag ores are found together with other lower-value polimetalic constituents, many of them containing high levels of heavy metals. Often, these secondary minerals are separated from the valuable ore and are treated as waste materials, ending in the mine tailings and dumps.

The authors have modified the font size from the figures.

The first main mention of a larger geographical area is emphasised through italics, later mentions being treated as normal text. If this stile of format is against the editing rules, we kindly ask the editor to remove the italic use for the respective instances.

The corrections were implemented.

The figures were marked from (a) to (f) and the legend was updated to include the respective details and the year.

The authors made the formatting consistent.

Name hyphenation was removed.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The manuscript has been significantly improved by the authors and can be accepted in presented form

Reviewer 2 Report

The text was thorougly improved from "Introduction" to logical structure and "References".

Following to this, the manuscript should be accepted in present form.