Assessing the Risk of Total and Available Potentially Toxic Elements in Agricultural Soil in Typical Mining Areas in Xiangjiang River Basin, Hunan Province
, Wenqing Liu 1, Haijiang Luo 3, Lihuan He 3, Haijiang Liu 3, Renji Xu 3, Linlin Zhang 3, Yeyao Wang 3, Guoping Wu 3 and Fusheng Wei 3,*
Round 1
Reviewer 1 Report
The researches aimed to assess the degree of contamination of rice grown in agricultural soil in mining areas located in Hunan Province in China and to find correlations between the concentration of potentially toxic element in rice and in soil as total concentration or as bioavailable concentration ( extractible with DPTA).
The study is of great interest taking in account its complexity with impact on food safety. The research is useful to a rational development and utilization of land resources.
Comments for author File: 
Comments.pdf
Author Response
Major Compulsory Revisions
1) I recommend to modify the abbreviation for potential toxic elements as PTE instead of PET The abbreviation “PET” is does not contain the initials of the term as usual, and the PET is an abbreviation often used in others fields.
Response: We have replaced the word "PET" with "PTE" in the whole manuscript.
2)Page 3 Lines 133-138 ‘’For the 85 sample sites, the total concentration of Mn ranges 102.4–2250.4 mg/kg, Cu 133 15.9‒993.4 mg/kg, Zn 47.8‒1680.8 mg/kg, Co 5.0‒26.6 mg/kg, Pb 0.0‒288.5 mg/kg, Cd 0.19‒ 134 24.25 mg/kg, Hg 0.09‒34.97 mg/kg for the soil samples (Table 1). The pH was 4.92‒7.86. 135 The mean concentrations of Mn, Cu, Zn, Co, Pb, Cd, and Hg were 431.2 ± 41.7 mg/kg, 45.3 136 ± 10 mg/kg, 4.9 ± 176.9 mg/kg, 13.29 ± 3.8 mg/kg, 49.15 ± 35.12 mg/kg, 1.31 ± 2.77 mg/kg, 137 and 0.66 ± 4.55 mg/kg, respectively. The mean values of the total Cu, Zn, Pb, Cd, and Hg 138’’ The text is difficult to pursuit. I recommend the presentation of the data in a table.
Response: We have presented the data on Table1.
3) Page 4: Figure 1 a The y axe title is not visible. Please improve the graphic of the figure.
Response: We have modified Figure1.
4) Page 5 Table 2 can be improved by defining N ( number of samples) and
Response: We have revised Table 2.
5) Page 6, lines 159-162: “There was a significant positive correlation between the total and bioavailable concentrations of all PETs in soil except Hg, The correlation coefficients of Cd, Pb, Mn, Cu, Zn and Co were 0.953, 0.486, 0.802, 0.996, 0.944 and 0.426, respectively. That’s suggesting that bioavailable concentrations are determined by the total concentrations, which is in agreement with a previous study [39]” The phrase should be improved as formulation (from grammatically point of view) and also as scientific meaning taking into account that Table 2 showed the correlation between total and bioavailable potential toxic element in soil and rice and not between the total and bioavailable concentrations of all PETs in soil.
Response: We have modified this paragraph and added a table.
6)Please give details on the cited study (reference [39])
Response: We have added the detail of the cited study.
7)page 6 lines 168-172 I recommend the improvement of the following phrase as to show better the difference or the resemblance between the studied elements: “For Cd, Cu, Co, and Pb, the total soil concentrations were higher than the bioavailable concentrations and concentrations in rice for four different pH groups. With an increase in the pH, the bioavailable concentration increased and concentration in rice varied slightly for Cd, bioavailable concentration and concentration in rice varied for Cu, and bioavailable concentrations decreased and concentrations in rice were unchanged for Co and Pb (Fig. 2).”
Response: We have modified this paragraph
8)Minor correction Page 8 Line 248 Previous studiy have shown that Cd uptake by plants is influenced by physical, chemical, and biological mechanisms, Please correct studiy
Response: We have revised the word.
Author Response File: Author Response.pdf
Reviewer 2 Report
Dear author(s),
I have read your interesting article thoroughly. You can find some of my suggestions, contributions and criticisms on the attached file. If you revise your manuscript taking into account these suggestions, contributions and criticisms, I hope that the article will be improved.
I wish conveniences.
Comments for author File: Comments.pdf
Author Response
Academic Editor:
Major Compulsory Revisions
1) Line13-14,You can use this sentences in introduction section.
Response: We have put this sentence into the introduction section.
2) Line17,The results indicated that the total concentrations of Cu, Zn, Pb, Cd, and Hg in soil had increased significantly compared with the 1980s.
Response: We have modified this sentence.
3) Line 37,reference[6,7].
Response: We have updated the literature.
4) Line107, DTPA
Response: We have added the full name before the abbreviation.
5) Line147, Pearson correlation analysis
Response: Spearman analysis method was used to reanalyze the data of this part, and this paragraph was modified.
6)Line149, The correlation of total Co in soil to that in rice was also 148 significant (p < 0.05) and positive (0.218).
Response: We have added the p value in Table 2 and modified the article.
7) Line160-161, There was a significant positive correlation between the total and bioavailable 159 concentrations of all PETs in soil except Hg, The correlation coefficients of Cd, Pb, Mn, 160 Cu, Zn and Co were 0.953, 0.486, 0.802, 0.996, 0.944 and 0.426, respectively.
Response: We have added Table 3 which related to these data and modified the article
8) Line191,the historical data
Response: We have revised the word into “background data”.
9) Line211-212, This finding implies that the desorp- 211 tion processes from the total concentrations to the bioavailable concentrations in soil were 212 significantly high but were lower during uptake or accumulation processes in rice.
Response: We have supplemented the results of chi square analysis in this paragraph.
10) Line229-230,check explanation about R2
Response: We have modified this paragraph.
11) Line248,studiy
Response: We have revised this word.
12) Line255,reference[52]
Response: We have updated the literature.
13) Line264, Note: Different letters within the same column indicate significant differences at p < 0.05.
Response: We have added the explanation of a,b,c.
14) Line 281, historical values,
Response: We have revised the word into “background data”.
Author Response File: Author Response.pdf
This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.
Round 1
Reviewer 1 Report
There are various concerns that should be addressed to this article. The subject of the article is within the general scope of the journal but the paper is not a
really new contribution to the topic. The aims of the paper is clearly exposed in the introduction. Materials and methods section is not exaustive (i.e. how have been
1978-1986 soil samples collected?) and, sometimes no standardized methods have been used (i.e. see "soil sample preparation"). Results are well explained. Conclusions
have to be merged. Editing of English language and style is required.
Here, all the points, line by line.
l.24. "PH" must be changed in "pH".
l.26. "study" has to be replaced with "studies".
l.28. Keywords: "heavy metal availability, Hunan Province" have to be changed because they are a repetition of title's words. Keywords have to be different from title
words.
l.28. "health risk evaluation" are not really keywords of the paper. Replace them.
l.43. Add ) after "[14]".
l.50. Add (Meixiang 2011) in the References paragraph and put the number at the place of the reference.
l.75-79. "2.1.1. Soil Sampling and Preparation": the preparation of soil samples was not so accurate and standardized. In fact, heavy metal concentrations data have to
be reported on dryed soil sample (soil sample usually have to be dryed at 105°C for at least 48 hour). In this way, data could be compared with data from other papers.
l.80-85. "2.1.2. Rice Sampling": describe better how rice samples have been harvest (how many plots? how big they were? how many plants have you harvested? etc...).
l.98-101. "2.2.3. Analyses of Heavy Metal Concentrations in Rice": were they dried samples?
l.114-115. How have been 1978-1986 soil samples collected? Have they been collected in the same points? Describe it in "Materials and Methods".
Figure 2. Add x-axes headings (for example "soil sample number"). Add a title ("Cd", "Pb", "Cu", "Zn", "Hg", "Mn", and "Co") in each sub-figure.
l.146. Add Wan et al. (2005) in the References paragraph and put the number at the place of the reference.
Figure 3. Add a title ("Cd", "Pb", "Cu", "Zn", "Hg", "Mn", and "Co") in each sub-figure.
l.171-224. "Conclusions": delete subparagraphs. Conclusions have to be in one paragraph.
l.179-180. Add (Duan et al. 2018) in the References paragraph and put the number at the place of the reference.
l.185. Change in "...and of a laboratory experiment...".
l.186. Change in "...in some sites, expecially for Cd".
l.198. Delete "of all samples".
l.201. Add (Wan et al. 2005) in the References paragraph and put the number at the place of the reference.
Author Response
- l.24. "PH" must be changed in "pH".
Response 1: Revised.
- 26. "study" has to be replaced with "studies".
Response 2: Revised.
3. l.28. Keywords: "heavy metal availability, Hunan Province" have to be changed because they are a repetition of title's words. Keywords have to be different from title words.
Response 3: Revised. Modified to”soil pollution, heavy metal, rice contamination, risk evaluation”.
4. l.28. "health risk evaluation" are not really keywords of the paper. Replace them.
Response4: Revised. Modified to “risk evaluation”
5. l.43. Add ) after "[14]".
Response 5: Revised.
- l.50. Add (Meixiang 2011) in the References paragraph and put the number at the place of the reference.
Response 6: Revised.
7. l.75-79. "2.1.1. Soil Sampling and Preparation": the preparation of soil samples was not so accurate and standardized. In fact, heavy metal concentrations data have to be reported on dryed soil sample (soil sample usually have to be dryed at 105°C for at least 48 hour). In this way, data could be compared with data from other papers.
Response 7: Revised. Operation method description error, modified to” Soil samples were collected from the upper horizon (0–20 cm) of soils across a 50 m × 50 m area on each sampling site. 5 samples were taken by plum blossom method, each sample was 25 cm × 25 cm, and then fully mixed. All soil samples were spread out on a piece of kraft paper (80 × 110 cm) in an air-drying room, in a layer with a thickness of 2 cm. After removing plant leaves, crushed stone and so on, the samples were dried naturally. Following grinding and passed through a 0.15 mm sieve was used for further analyses.”
l.80-85. "2.1.2. Rice Sampling": describe better how rice samples have been harvest (how many plots? how big they were? how many plants have you harvested? etc...).
Response 8: Revised.Rice samples were collected from point to point of soil samples, Take 5 samples of 25 cm × 25 cm for each site, then fully mixed.
l.98-101. "2.2.3. Analyses of Heavy Metal Concentrations in Rice": were they dried samples?
Response 9: Yes, They were
l.114-115. How have been 1978-1986 soil samples collected? Have they been collected in the same points? Describe it in "Materials and Methods".
Response 10: I have not collected the 1978-1986soil samples, I just quote historical data, I will modify it in the text to make the expression clearer
Figure 2. Add x-axes headings (for example "soil sample number"). Add a title ("Cd", "Pb", "Cu", "Zn", "Hg", "Mn", and "Co") in each sub-figure.
Response 11: Revised.
l.146. Add Wan et al. (2005) in the References paragraph and put the number at the place of the reference.
Response 12: Revised.
Figure 3. Add a title ("Cd", "Pb", "Cu", "Zn", "Hg", "Mn", and "Co") in each sub-figure.
Response 13: Revised.
l.171-224. "Conclusions": delete subparagraphs. Conclusions have to be in one paragraph.
Response 14: Revised.
l.179-180. Add (Duan et al. 2018) in the References paragraph and put the number at the place of the reference.
Response 15:Revised.
l.185. Change in "...and of a laboratory experiment...".
Response 16: Revised.
l.186. Change in "...in some sites, expecially for Cd".
Response 17: Revised.
l.198. Delete "of all samples".
Response 18: Revised.
l.201. Add (Wan et al. 2005) in the References paragraph and put the number at the place of the reference.
Response 19: Revised.
Author Response File: 
Author Response.docx
Reviewer 2 Report
Dear authors
Most of our suggested changes are of format and style rather than important changes in the structure and content of the work.
Most or comments and recommendations to improve your paper are in the attached document .pdf
Our main complaints about it is about the bibliographic review. We think can be improve because are important references are not cited in the paper. For example:
Du F, Yang Z, Liu P, Wang L. Accumulation, translocation, and assessment of heavy metals in the soil-rice systems near a mine-impacted region. Environ Sci Pollut Res Int. 2018 Nov;25(32):32221-32230.
Wang Z, Hong C, Xing Y, Wang K, Li Y, Feng L, Ma S. Spatial distribution and sources of heavy metals in natural pasture soil around copper-molybdenum mine in Northeast China. Ecotoxicol Environ Saf. 2018 Jun 15;154:329-336.
Zhang J1, Li H2, Zhou Y3, Dou L4, Cai L4, Mo L3, You J5. Bioavailability and soil-to-crop transfer of heavy metals in farmland soils: A case study in the Pearl River Delta, South China. Environ Pollut. 2018 Apr;235:710-719.
He L, Zhong H, Liu G, Dai Z, Brookes PC, Xu J.Remediation of heavy metal contaminated soils by biochar: Mechanisms, potential risks and applications in China. Environ Pollut. 2019 Sep;252(Pt A):846-855.
Rai PK, Lee SS, Zhang M, Tsang YF, Kim KH.Heavy metals in food crops: Health risks, fate, mechanisms, and management. Environ Int. 2019 Apr;125:365-385.
Shifaw E. Review of Heavy Metals Pollution in China in Agricultural and Urban Soils. J Health Pollut. 2018 Jun 6;8(18):180607.
Sodango TH, Li X, Sha J, Bao Z. Review of the Spatial Distribution, Source and Extent of Heavy Metal Pollution of Soil in China: Impacts and Mitigation Approaches. J Health Pollut. 2018 Mar 12;8(17):53-70.
Yang Q, Li Z, Lu X, Duan Q, Huang L, Bi J. A review of soil heavy metal pollution from industrial and agricultural regions in China: Pollution and risk assessment. Sci Total Environ. 2018 Nov 15;642:690-700.
We recommend an extensive review of literature to improve the introduction.
Comments for author File: Comments.pdf
Author Response
Please see the file in the attachment.
Author Response File: Author Response.docx
Reviewer 3 Report
Review Report of “Assessing total and bioavailable heavy metals in soil 2 and their influence on rice in six cities of Hunan 3 Province, China”
Yu et al. have investigated the total heavy metal concentration in the soil as well as bio-availability by analyzing soil and rice samples from six cities. The title of the manuscript is very attractive and sets the expectation of the reader very high but the main text doesn’t is very disappointing. The manuscript is written in a very simple and clear manner but it lacks reasoning at each point and makes it feel more like reading a report than a research article. It needs major revision where a discussion that is more scientific should be included and comparison with other studies should be shown clearly. I reject the manuscript in the current version.
I am mentioning some of the points for the revision. They are:
Line 70: Source of historical data?
Line 93: Is this an ASTM method or any standard method?
Line 133: Pearson r value below 0.5, I would not call them positively correlated. Hence, all the discussion based on that is incorrect.
Line 151-154: Provide reasons. Why effect of soil pH is seen only for Cd and CU and not for Pb and Co.
Line 180: Provide more information on the type of industries?
Line 211-212: Please comment more on what are the important parameters affecting the bio-availability of certain metals and not the others?
Is there any relationship with soil porosity, the oxidation state of the metals affecting their solubility?
Line 217: Please also comment on which soil samples were more acidic than the rest...More information on location-wise segregation of metal uptake capacity of the soil is also required.
Author Response
- Line 70: Source of historical data?
Response 1: Pan youmin. Soil background values and research methods in Hunan Province. Environmental Science Press: Beijing, China.1988.
- Line 93: Is this an ASTM method or any standard method?
Response 2: It is an national standard of China, GB/T 23739-2009.
- Line 133: Pearson r value below 0.5, I would not call them positively correlated. Hence, all the discussion based on that is incorrect.
Response 3:Based on correlation analysis, many scholars have different opinions on the significance of r and p values. First of all, most scholars think that if p value is less than 0.05, it means significant correlation; if p value is less than 0.01, it means extremely significant correlation. The closer r is to 1, the stronger the correlation is. Secondly, for r value, many scholars think that more than 0.3 is weak correlation, and more than 0.5 is correlation. From this point, our analysis results are not unrelated. In addition, I have also consulted many similar research literature. In their research results, there are also cases where r value is less than 0.5 and P value is less than 0.05 or 0.01. They all think that are relevant. Based on the above reasons, we hope you could agree with our opinion. The following are some references containing similar research results. For example:
[1] Li-bo Pan, Jin Ma * , Xian-liang Wang, Hong Hou. Heavy metals in soils from a typical county in Shanxi Province, China:Levels, sources and spatial distribution. Chemosphere148(2016)248-254.
[2]Xiaoyang Liu, Huading Shi, Zhongke Bai, Wei Zhou, Kun Liu, Minghao Wang, Yujie He. Heavy metal concentrations of soils near the large opencast coal mine. Chemosphere. 244 (2020) 1-9.
[3] Lu Sun, Dengkui Guo, Ke Liu, Hui Meng , Yuejun Zheng, Fuqiang Yuan , Ganghui Zhu. Levels, sources, and spatial distribution of heavy metals in soils from a typical coal industrial city of Tangshan, China. Catena. 175 (2019) 101–109.
- Line 151-154: Provide reasons. Why effect of soil pH is seen only for Cd and CU and not for Pb and Co.
Response 4: Data analysis and corresponding support are supplemented.
- Line 180: Provide more information on the type of industries?
Response 5: Some information about the concentration and source of heavy metals at the site were added.
- Line 211-212: Please comment more on what are the important parameters affecting the bio-availability of certain metals and not the others?
Response 6: Revised and supplemented
- Is there any relationship with soil porosity, the oxidation state of the metals affecting their solubility?
Response 7: Yes, there is. I have added some discussion to this in the manuscript.
- Line 217: Please also comment on which soil samples were more acidic than the rest...More information on location-wise segregation of metal uptake capacity of the soil is also required.
Response 8: The pH range and the conversion rate of heavy metals in soil under different acidity conditions were analyzed, and the effects of acidity on the conversion were discussed.
Author Response File: Author Response.docx
Round 2
Reviewer 3 Report
The scientific content of the revised manuscript "Assessing total and bioavailable heavy metals in soil and their influence on rice in six cities of Hunan Province, China" by Yu et al. is still lacking scientific explanations for their observations which makes it unfit for the publication.
Hence, I reject this manuscript in the current state.
