Arsenic Occurrence and Cycling in the Aquatic Environment: A Comparison between Freshwater and Seawater

Round 1

Reviewer 1 Report

This review highlights the arsenic occurrence and cycling in aquatic environments, which have played a pivotal role in the understanding of the environmental behavior of arsenic and improving arsenic risk evaluation. The differences between freshwater and seawater with reference to the concentration as well as speciation and distribution patterns of arsenic were also discussed. The subject of this review was innovative and the contents were richness. Therefore, this paper can be accepted, after some revisions are made.

Authors can consider the following recommendations before this article is published.

Introduction

Line 56-59: Arsenic pollution in aquatic systems has caused disaster in human drinking water in more than 20 countries, including India, Bangladesh, China, the USA, and Argentina (Mandal and Suzuki 2002; Guo et al., 2008; Villaescusa and Bollinger 2008), and has received increasing international attention. I suggest using some recent literature to support these data.

 Line 92-95: “Therefore, this study describes the sources of arsenic in aquatic environments and pays close attention to the occurrence of arsenic in aquatic environments, including freshwater, seawater, and the associated sediments. The potential differences in the behavior of arsenic in these different environments were compared.” Is there any existing literature on comparing the differences between freshwater and seawater?

 2. Sources of arsenic in the aquatic environment.

In this part, the author can add some information about the differences between the sources of arsenic in freshwater and seawater.

 Line 128-131, Geothermal waters, which commonly contain elevated arsenic concentrations mixed with drinking water sources, give rise to arsenic contamination, as reported in a geothermal field in Mexico, where the highest recorded arsenic concentration was 73,600 μg/L (Birkle et al., 2010). These high concentrations of arsenic are inorganic arsenic or organic arsenic？

Please add “average or range” behind the second column header (Arsenic concentration) in Table 1.

Line 250-252: In general, compared with the concentrations of arsenic, which varies over several orders of magnitude, arsenic speciation shows similar characteristics, but tends to be site-specific. There is an extra space between two words of “which” and “varies”.

 Line 295-297: Some species of bacteria, such as dissimilatory arsenate-respiring prokaryotes, utilize the reduction of arsenic to obtain the energy required for survival. The font size of words in this paragraph is inconsistent.

 4. Arsenic occurrence in seawater

Please add “average or range” behind the second column header (Arsenic concentration) in Table 2.

 Line 387-389: The mean arsenic concentration in the eastern Atlantic Ocean was 0.97 μg/L, a relatively constant and higher average concentration was reported in deep water (1.5 μg/L) (Waslenchuk, 1978). The number of decimal places reserved in this sentence is inconsistent.

Line 557-558: In comparison, sulfur is more abundant in marine sediments. Is there any updated literature to prove this point?

 6. Conclusions and future perspectives

Please add some prospects of future research in this section.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper compared arsenic occurrence and cycling in freshwater and seawater. This review provides deep insights into arsenic occurrence and cycling in aquatic environments, and the results 34 can be used to improve arsenic risk evaluation.

I suggest it is worth to be published after minor revision.

I suggest the authors read the guideline of the journal carefully before the correction. I have some questions that I think should be addressed in the revised manuscript:

1.     Line 112: Two 'others' in Figure 1 will be misleading.

2.     Line 225: The Table 1 is not visible.

3.     The figures in the paper are incomplete.

4.     Heading should be placed above the table.

5.     In “Reference”: the format should be consistent and revised according to the guideline. For example, the format of author’s name is not correct, the information of the reference should be complete, and the full name and abbreviation of journal title should not appear at the same time (e.g., number 5, 6, 9, 22, 24, 25, 40, 41, 66, 178, 182, 4199, 203, etc.).

Author Response

Please see the attachment. 

Author Response File: Author Response.pdf

Reviewer 3 Report

The abstract section is very weak. Several figures are not completely visible, making it difficult to judge the accuracy. Tables are not presented properly, and table captions are placed at the bottom. The author’s observations are placed under inappropriate headings. Conclusions are not strongly supported by your data. 

This manuscript did not follow the journal-specific guideline for references. The authors used 46 references in the text but did not add to the reference list; and they added 52 references to the list which never used in the text. 

 

Overall, the manuscript is very poorly prepared. Therefore, I recommend rejecting this manuscript.

Other comments -

Abstract: The abstract part is written very superficially.
Line 102-105: Under the heading of “Natural Sources of Arsenic” the authors emphasized the anthropogenic sources, which is not appropriate.
Table 1: There is no table 1.
Line 239-252: These are general information about the global arsenic scenario, which can be used in the introduction. When you are talking about arsenic in freshwater this is not appropriate here.
Figure 2: Half of figure 2 is missing.
Line 396: The table title should be on top of the table
Figure 3: Half of figure 3 is missing.
Line 626: Pollution and contamination are different things. The authors have used them alternatively to mean the same, which is not acceptable.
Line 637: The authors on several occasions mentioned “biologically mediated reaction or biotransformation”. However, they did not discuss in detail which microorganisms or how they work; so, the conclusion related to biotransformation is questionable.
Line 654-659: This does not make clear sense about future research.

The authors added the following references to the list but did not use them in the text. [1, 5, 6, 21, 35, 38, 51, 54, 55, 65, 68, 72, 76, 79, 80, 84, 89, 98, 102, 105, 106, 108, 113, 115, 116, 117, 129, 130, 135, 138, 140, 142, 143, 146, 147, 149, 152, 154, 155, 160, 161, 164, 166, 176, 178, 188, 189, 192, 197, 202, 203, 206]

Line 80: Abdelghani et al., 1981; used in the text but not listed in the References
Line 86: Mok and Wai, 1994); used in the text but not listed in the References
Line 102: Boyle and Jonasson, 1973; used in the text but not listed in the References
Line 127: Belkin et al. 2000; used in the text but not listed in the References
Line 144: Peters et al. 1999; used in the text but not listed in the References
Line 208: Jonnalagadda and Nenzou, 1996: used in the text but not listed in the References
Line 209: Rango et al. 2013; This is probably 2014?
Line 211: Whilst Seror-Armah et al. (2006); used in the text but not listed in the References
Line 229: Azcue et al., 1995; used in the text but not listed in the References
Line 237: Smedley et al., 1996; used in the text but not listed in the References
Line 243: Kirchner, 1998; used in the text but not listed in the References
Line 250: Chakraborty et al., 2015, This is probably 2014?
Line 317: Francesconi and Kinniburgh, 2002; used in the text but not listed in the References
Line 332: Wang et al., 2013; Zhang et al., 2011; used in the text but not listed in the References
Line 339: Hasegawa et al., 2009; used in the text but not listed in the References
Line 340: Sanders, 1983; used in the text but not listed in the References
Line 342: Hasegawa et al., 2001; used in the text but not listed in the References
Line 343: Rahman et 2011; This is probably 2012?
Line 351: Hasegawa et al., 2011; used in the text but not listed in the References
Line 353: Sanders and Riedel, 1993; used in the text but not listed in the References
Line 354: Hasegawa et al., 1999; used in the text but not listed in the References
Yusof et al. (1994); used in the text but not listed in the References
Ren et al. (2010); used in the text but not listed in the References
Cutter et al. (1998); used in the text but not listed in the References
Maher (1985); used in the text but not listed in the References
Seyler and Martin (1990); used in the text but not listed in the References
Navarro et al. (1993); used in the text but not listed in the References
Ishikawa et al. (1987); used in the text but not listed in the References
Chang et al. (2011), This is probably 2012
Davies (1974); used in the text but not listed in the References
Bełdowski et al. (2015); used in the text but not listed in the References
Mirlean et al. (2001, 2003, 2003a); used in the text but not listed in the References
Mirlean et al. (2014); used in the text but not listed in the References
Line 426: Waslenchuk, 1978; used in the text but not listed in the References
Line 438: Francesconi and Edmonds, 1997; used in the text but not listed in the References
Line 447: Glabonjat et al., 2017; This is probably 2018?
Line452: Hanaoka et al., 1995; used in the text but not listed in the References
Line 467: Neff 1997; used in the text but not listed in the References
Line 504: Kaise et al., 1997; This is probably 1998?
Line 510: Maeda and Ohki, 1998; used in the text but not listed in the References
Line 512: Zhang and Wang, 2012, used in the text but not listed in the References
Line 515: Schaeffer et al., 2006; used in the text but not listed in the References
Line 573: Anawar et al., 2011; used in the text but not listed in the References

Author Response

Please see the attachment. 

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

The manuscript summarized the origin, distribution, and cycling of arsenic in the environment. Overall, the authors did a good job and the manuscript is improved compared to the previous version.
However, the authors need to pay attention to the accuracy of references and follow the journal-specific guideline. Please revise the manuscript according to the comments below-

The following references were used in the text but not added to the reference list:
Ashley and Lottermoser (1999);
Ferguson and Gavis (1972);
Francesconi and Edmonds, 1996);
Hasegawa et al., 1999;
Jerry, 2009;
Jia et al. (2017);
Lerda and Prosperi (1996);
Maeda and Ohki, 1998;
Matheus et al. (2019);
McLaren and Kim (1995);
Nyantakyi et al. (2019);
Pettine et al. (1992, 1997);
Robinson et al. (1995b);
Sá et al., 2015;
Seyler and Martin (1990);
Wenzel, 2013;
Wilkie and Hering (1998);
Williams et al. (1996);
Zhang et al., 2013;

The following references were added to the reference list but did not use in the text:
Fendorf et al., 2010;
Maeda and Ohki, 1988;
Zhang et al., 2014;