Sewage Sludge in Agricultural Lands: The Legislative Framework in EU-28

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript addresses the critical and evolving issue of sewage sludge (SS) management in agriculture within the EU legislative framework, particularly relevant given recent updates to Directive 86/278/EEC. The authors provide an extensive review of national and EU-wide legislation, identifying discrepancies and gaps while integrating socioeconomic and environmental perspectives. The use of R for statistical analyses and QGIS for geospatial mapping enhances the credibility and clarity of the results. The bibliographic methodology is sound, with a clear rationale for inclusion and exclusion criteria.

Comments and Suggestions for Improvement

Clarity and Cohesion: The abstract could be improved by streamlining the narrative to focus on key findings and implications, emphasizing the gaps in current EU frameworks. Certain sections, especially the discussion, repeat earlier content (e.g., challenges of SS pollutants). Consolidating these points could enhance readability.

Analysis Depth: While the manuscript identifies regional disparities, further elaboration on why these disparities exists (e.g., cultural, economic, or climatic factors) would provide more context. Consider including case studies or in-depth comparisons (e.g., Germany vs. Southern EU states) to illustrate the practical implications of legislative differences.

Emerging Pollutants: The manuscript highlights microplastics (MPs) and pharmaceuticals but stops short of discussing potential monitoring or mitigation strategies. Addressing these aspects could enhance its applicability for policymakers.

Data Representation: Figures and tables are informative but could benefit from more concise legends to ensure accessibility for non-experts. Additionally, some graphs (e.g., Fig. 5 on SS treatment methods) are dense and may need simplification.

 

Recommendations Section: The conclusion effectively summarizes findings but lacks actionable recommendations for harmonizing EU-wide legislation

Author Response

We want to welcome all the valuable insights and comments of the esteemed Reviewer. 
Adhering to the comments and suggestions, we provide the following feedback:

• As per the Reviewer's suggestions, we have revised most of the original abstract to 
enhance its readability. We focused on the key findings and their implications while 
clearly articulating the high-volume diversity gap and the lack of regulatory measures for 
microplastics (MPs) and other common soil pollutants in the EU's legislative 
frameworks. 

• Within the initial article file, a concise paragraph was dedicated to Germany and other 
Northern European Member States (MS) known for their rigorous, strict HMs limit values. 
To enhance further, as guided by the Reviewer, the pivotal role of some MS, such as 
Germany and other Northern European states, we incorporated additional context and 
data referring primarily to Germany's and the Netherlands's pivotal role in guiding the 
EU-28 in the management and addressing HMs referring this time on the EU Regulation 
No. 1223/2009. The newly added contact again highlights the stringent limit values set 
forth by Germany compared, even with the USA and Canada.

• The latest version of the article file has been enhanced with extra information and data 
related to MPs. The Discussion Part of the newly submitted article outlines a current 
identification strategy for MPs that is environmentally and economically friendly and 
involves the application of sustainable fly ash that incorporates iron ions. Furthermore, 
the primary contemporary methods for monitoring are delineated.

• The newly submitted article has incorporated new digital maps, resized, with even 
higher resolution, and added extra information (as guided by the second Reviewer), such 
as the Scale and the North Arrow, to improve comprehension and clarity.

• In the Discussion part of the recently submitted article, the imperative of achieving a 
consensus on European and Global scales is highlighted (lines 402-404). This is 
especially important for selecting effective and reliable in-situ measurement 
techniques, as laboratory science has provided a range of accurate and detailed 
methodologies. The suggestion to embed purification protocols within future legal 
frameworks represent a significant and necessary action to address the background 
contamination and its associated risks (lines 404-406). Recognizing that soil 
contamination from MPs represents a complex and extensive challenge influenced by 
human actions, environmental conditions, and societal decisions, we propose that the EU 
MS collaborate to establish a cohesive strategy for defining and naming MPs (lines 389
392).

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

General Comments:

This manuscript presents a detailed analysis of the processes and obligations of EU (member states) MS regarding sewage sludge’s management, treatment, and agriculture amendment. The manuscript is well written with suitable methodology and analytical tools. The literature review, theoretical analysis, and econometric analysis sections of the article can draw relevant findings. This study has essential implications for understanding SS usage differences in EU countries. Therefore, I believe that this study has met the criteria for publication. I only have little suggestions about some illustration issues .

Detail Comments:

1. When proper nouns appear for the first time, such as “Sewage Sludge”, either in the Abstract or in the main text, they should be provided throughout before abbreviations are used.

2. For Figure 1, please consider image re-arrangement and resizing. For the three types of data, please use different colors to distinguish them. Please provide the scale and north arrow.

3. For Figure 2, also please provide the scale and north arrow.

4. Figures 3 and 4 should be separated. The same goes for Figure 5 and 6.

Author Response

We want to thank the esteemed Reviewer for pointing out that the study paper meets the criteria 
for publication. Accordingly, and following the Reviewer’s comments: 
• The article has been meticulously reviewed to confirm that all proper nouns are fully 
presented before their respective abbreviations. Additionally, we have made several 
corrections highlighted in the resubmitted document. 
• The revised submission incorporates newly developed maps, which have been resized 
and repositioned to enhance their alignment with the article's content. In line with the 
Reviewer’s suggestions, these maps have been produced in various colour palettes to 
improve their clarity and ease of interpretation.  
• Each newly produced map in the article now contains North Arrow and the Scale. 
• Figures 3, 4, 5, and 6 were separated.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The article discusses a relevant topic – the utilization of sewage sludge. Despite existing methods for wastewater sludge treatment, this is an essential aspect of environmental protection and the production of value-added products. The author has conducted research into the experience of EU countries in the use of sewage sludges. The paper is accompanied by tables and maps. However, the size of some of the maps may be a drawback. We would appreciate it if the author could provide better-sized maps. Overall, the article is well-written. There are no significant issues with the results or discussion. However, I would suggest that the author consider how the experience of  EU-28 countries could be relevant for other regions, such as the Asian-African continent or Russia, which faces similar recycling challenges.

 

Author Response

We would like to thank the esteemed reviewer for appreciating our work.  
• We are grateful for your constructive observation about the size of specific maps in the article. Considering your feedback, we have undertaken a comprehensive resampling of these maps, resulting in a more adequate size for visualization. Moreover, we have adjusted their position arrangement in the article to improve the viewing experience. 
• Following your valuable suggestions, we have re-submitted the article with the inclusion of new countries outside the EU-28, acknowledging the worldwide significance of the topic. Under your request, we have added Russia and various African nations. The Eastern Mediterranean - Middle East and North Africa (EMMENA) region has been designated in the article as the representative current Affiliation (Eratosthenes Centre of Excellence – Limassol, Cyprus) of several authors, actively collaborates with relevant private and government organizations and stakeholders in these countries. We have also incorporated Jordan, Algeria, and Egypt to ensure a more holistic perspective.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Thanks for revising the work, all the best