Evaluation and Source Analysis of Heavy Metal Pollution in Grassland Soils under Different Management Modes in Altay, Xinjiang

Round 1

Reviewer 1 Report

Review

 Evaluation and source analysis of heavy metal pollution in grassland soils under different management modes in Atlay, Xinjiang

 

 

In the study, the authors have assessed the level of heavy metal pollution within several different grassland soil types. With a focus on metals such as Cd, As, Pb and Cr. The authors were able to assess the heavy metal pollution level for each metal as well as rank their pollution rate (Cd and Ni being observed to pollute all the tested grassland types) in the different grassland types tested in the study. The contribution of different anthropogenic sources of these metals was also assessed using the APCS-MLR model.

 

Overarching comments

The study meets all the objectives it set out to understand. The paper for the most part was grammatical well written. The study provides information regarding the disposition of these heavy metals within the grasslands and how they compare to the normal baseline. Providing this information can guide remediation projects to prioritize certain metals (Cd and Ni) in order to achieve more efficient metal removal.  

 

Suggestion Line 117: The authors may want to include a short description below table 1 or within the text that describes the terms Pi, Pn and Igeo. The reason I make this suggestion is to enable readers of the article who are interested in the work but are not fluent in the discipline to be able to understand, thus ensuring a wider readership of the article.

Suggestion lines 339-343: I think the authors should relook at this section and try to relate the conclusion more to the study at hand.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Materials and methods

The methodology is written in a non-clear way. Soil samples were taken at a depth of 0 – 10, 10 – 30 and 30 – 50 cm - have metals from these three depths been tested? There is no metal analysis at individual depths in the article text. A figure of the test object with marked sampling points for each type of grassland should be made. It is also worth showing on the figure sources of pollutions.

Results
  It is worth writing metals in series, this will facilitate the interpretation of results.
E.g:
Analysis of average values of metal concentrations in grassland soils showed that they can be ordered in ascending order...
The distribution of metals in the tested soils is consistent with the distribution of elements in the geochemical background of Xinjiang soils...
The article does not include analysis of metal tests at a depth of 0 – 10, 10 – 30 and 30 – 50 cm.

Test results should be interpreted taking into account the types of grassland.

 Analysis of soil contamination with heavy metals -Nemero Index, Geological Accumulation Index - is written chaotically and very difficult to read. This should be written in a clear and simple way.
Nemero Index
"The evaluation results of the Nemero pollution index show that the mean values of PN for the comprehensive pollution index of heavy metals in the soil of five types of grass- land were 1.42 (1 < PN ≤ 2, light pollution), 1.45 (1 < PN ≤ 2, light pollution), 1.94 (1 < PN ≤ 153 2, light pollution), 3.67 (PN > 3, heavy pollution) and 1.63 (1 < PN ≤ 2, light pollution)" - this should be explained clearly

Geological Accumulation Index
Describe the index referring to the table and graphs in the methodology
Interpretation can be started in this way - Analysis of soil contamination with grassland with metals based on Igeo showed that the largest contamination concerns Ni and Cd in the case of ……, Igeo values for Ni and Cd  were slightly higher than 0 (graph..), wich is suggesting that the soil is not contaminated. Igeo values for....... were slightly different. Soils were least contaminated………….. In more than ...........% samples Igeo values did not exceed classes 0 and 1 ...........

It is also worth shortening the text of factor analysis to take into account the most important aspects.

 Discussion

In the discussion, I would combine the characteristics of heavy metal pollution with the identification of sources of pollution. The discussion will be more consistent this way.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Paper can be accepted in present form

Author Response

Please see the attachment.

Author Response File: Author Response.pdf