Heavy Metals in Wetland Ecosystem: Investigating Metal Contamination in Waterbirds via Primary Feathers and Its Effect on Population and Diversity

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Author(s),

In this study, the researcher(s) evaluated the metal content (As, Cd, Co, Cr, Cu, Pb, Ni, and Zn) in the primary feathers of dead carcasses of 10 different waterfowl species (tablo 1, line 137) obtained from important wetlands (Point Calimere Wildlife Sanctuary, Pallikaranai Marshland, Perunthottam freshwater lake, Pulicat Lake) in India. Moreover, They compared their results with metal results obtained from birds studied in other parts of the world. Wetlands are critically important ecosystems and are home to many living organisms. Determination of elemental pollution in wetlands, which are important feeding and breeding habitats for waterfowl, is necessary for sustainable management. The study contains new information and will be of interest to scientists from different disciplines.The paper is well written, has current and important data, and should be of great interest to the readers. The introduction and others sections provide useful information for the readers. The paper has a potential to be accepted, but some important points have to be clarified or fixed before we can proceed and a positive action can be taken.

I here summarize this points:

1- Brief methodology (digestion method and instrumental method) information should be given in the abstract

2- The resolution of the map given in Figure 1 is low and not clear. It should be renewed.

3- In all text, “marsh land” should be written as “marshland”.

4- If recovery (%) calculations were performed using certified reference material before determining the concentrations of elements by ICP MS, it should be given in the subheading 2.4. Quality control and analytical procedure.

5- The presence of 8 elements (As, Cd, Co, Cr, Cu, Pb, Ni, and Zn) was investigated in primary bird feathers. However, Ag element is also included in Table 2. The reason for it should be explained. 

6- In the text, it is stated that according to the data obtained, the most Zn element was found in the feathers of 10 species and the least As element was found. The reason for this determination should be emphasised and stated precisely.

7- Whether there is a relationship between bird mortality and toxic element concentrations should be stated in the conclusion.

The content of the article in accordance with the aims of the Soil Systems

The article is scientifically sufficient.

Keywords are well chosen so that the article can be found by indexes.

The literature has been adequately critical, current and internationally evaluated by the authors.

The language of the article is correct and clear.

The discussion part is comprehensive in the paper.

Tables are figures well designed and necessary.

Acceptable after minor revisions.

Author Response

Thank you so much sir for your guidance, suggestions and comments to improve the article.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

After reading the manuscript, which contains an interesting approach to detect metal accumulation in a wetland system by analysing concentrations in the feathers of dead birds, I conclude that depth and a critical view in the discussion and conclusion is missing. The paper has an alarming voice but no risk assessments is performed to proof any health effects on the birds, environment, or human in and around the wetland. Comparison is made between the mangrove areas but comparison to international threshold values or relevant other studies is lacking. The mechanisms of uptake of the metals by the birds are not clearly described. A general lack of academic language and spelling and grammar mistakes are present. The discussion should be more focussed and made more concise.

 

L24 In fact, the metal contamination is one of the most significant threats to wetland habitats. Is that so??

L46-48 Sentence one and two give confusing double information. Rewrite

L51-53, the same information is repeated

L 53, verb is missing ‘might be lost’

L 55 , again verb is missing, is affected by?

L61-63, to general, can be affected, is not always the case

L 64 ‘s hown’ ?

L 69 ‘we want’ no academic style, we aimed to, we had the objective to ….

L72 verb missing…

L101 will you protect waterbirds by comparing? The results are rather a support for stakeholders, environmental agencies to develop protection measures…

L106 The study was carried out from four wetlands , carried out at

Table 1. Rewrite description, details are given on the type of waterbirds, not on the feathers..

L149 Why collect more than three? How was the selection made on which feathers to use.. Where they always the same size and weight?

L90 The Arsenic (As) was higher in Large crested ter: the arsenic concentrations were higher

L244 I lack a discussion on the potential health effects for birds due to the metals stored in their feathers. Can it also be considered to be a form of protection? Furthermore, are these birds consumed? Who can perceive negative health effects from the consumption (including feathers)?

L251 In fact, the current study examined the metals that are directly associated with trophic structures. How was that studied? Explain further in methodology and results.

L252 The study revealed critical results on the concentration of 252 metals in waterbirds examined. Why are the results critical?

L358 The research showed a wide range for metals in waterbirds. No, iIt showed the presence of XX metals in the feathers of waterbirds…

L360 what is principal?

L368 not all metals are toxic….

L 371 Throughout the paper very strong and general statement are made but proof is lacking of for the area under study. E.g. ‘The nutritious foods for examples fishes, molluscs and crustaceans are collected from the wetlands and these foods are consumed by the human society, which will cause various disorder and disease to human.’

Comments on the Quality of English Language

A general lack of academic language and spelling and grammar mistakes are present. 

Author Response

Thank you so much sir for your guidance, suggestions and comments to improve the article.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

I agree with adjustements made by the authors.

However, a response lacked to the comments that were raised in my previous feedback. "The paper has an alarming voice but no risk assessments is performed to proof any health effects on the birds, environment, or human in and around the wetland. Comparison is made between the mangrove areas but comparison to international threshold values or relevant other studies is lacking. The mechanisms of uptake of the metals by the birds are not clearly described. " 

L346 "Nevertheless, the results of the present study showed that the waterbirds are carrying toxic metals in their body which is influencing their physiology with adverse effects."  How did the study proof the presence of averse effects? What are these adverse effects? By measering the presence of metals in the feathers , no adverse effects were measured, this would involve a completely different set-up. 

 

 

Comments on the Quality of English Language

Academic style is still lacking in parts. For example:

L278 The lake gets => the lake receives

Author Response

Response to Reviewer 2 Comments

 

 

Comments and Suggestions for Authors

I agree with adjustements made by the authors.

However, a response lacked to the comments that were raised in my previous feedback. "The paper has an alarming voice but no risk assessments is performed to proof any health effects on the birds, environment, or human in and around the wetland. Comparison is made between the mangrove areas but comparison to international threshold values or relevant other studies is lacking. The mechanisms of uptake of the metals by the birds are not clearly described. " 

Response:

Yes, the study did not assess the level of metals and their impact on waterbirds.

The comparison of metals between the current study and the other studies are discussed and which is presented in the discussion section. Kindly see the highlighted with yellow colour. We have also added the threshold level of each metal and their impacts are also mentioned. This is for your kind information. Please read the discussion section highlighted with yellow colour fonts. Thank you so much.

L346 "Nevertheless, the results of the present study showed that the waterbirds are carrying toxic metals in their body which is influencing their physiology with adverse effects."  How did the study proof the presence of averse effects? What are these adverse effects? By measering the presence of metals in the feathers , no adverse effects were measured, this would involve a completely different set-up. 

Response:

Yes, we accept the critical comments of the reviewer. However, we did not conduct a lab study on metals and their impact on waterbirds. But, we have discussed the results of the present study with the results of the published literature globally. The accumulation of metals in the waters is a long-term exposure. Therefore, we have confirmed that the waterbirds are at risk because the level of metals in the feathers of waterbirds are higher than the other waterbirds examined in the rest of the country. Therefore, we described the word “adverse risk/effects” for example, reference numbers 29 and 57.

But, we decided to draw the word from the introduction (please see lines 96-97); in the disscusion part (lines 244 and 341). Thanks to the reviewer for your critical and more scientific analysis of the results and discussion. Thank you so much.

 

 

 Comments on the Quality of English Language

Academic style is still lacking in parts. For example:

L278 The lake gets => the lake receives

Response:

Yes, the word “gets” is replaced as “receives”. The language is enriched and revised as per your critical comments and suggestions. Thank you so much.

 

We appreciate your insightful comments and recommendations. Really, the reviewer has done extraordinary reviews and placed novel suggestions in the manuscript. Sincere appreciation.