Peer review of: Arsenic contamination of Bangladesh aquifers exacerbated by clay layers (2020)

 

 

REVIEWERS' COMMENTS: 
 
Reviewer #1 (Remarks to the Author): 
 
Whilst I still do not agree entirely with the conclusions of the manuscript, there is a margin here for 
disagreement which should not of itself preclude publication. 
 
The authors have substantively revised the manuscript on two occasions in response to reviewers' 
comments and now have a revised manuscript that, in my opinion, should be published. 
 
No doubt, not all may agree with the conclusions, but the conclusions are now argued reasonably well 
and will attract interest and debate. 
 
 
 
 
 

Reviewer #2 (Remarks to the Author):

Comments to 2nd revision of: 

Arsenic contamination of Bangladesh aquifers exacerbated by clay layers 

Dear Editor, dear Authors 

I now find the manuscript very much improved in readability/clarity. The MS is now much more to-
the-point and textual precision has been improved in many places. 

This time I took the liberty of simply commenting in the MS Word *.docx file. To clarify my points, I 
further took the liberty of editing directly in the document. I do not mean to push my 
formulations, but I did this in order to clearly illustrate the (low) level of further modifications to 
the MS that I suggest the Editor should request before final acceptance. 

Reference to line numbers in the following is to the *.docx file, with Microsoft Word’s Track 
Changes set to show ‘All Markup’. 

As stated, the MS reads very well. But regarding the modifications: 

1.

I maintain that the authors should clarify the type of aquifer investigated namely aquifers
deposited post-LGM and before Holocene, which indeed may contain both grey and orange
sands, but which have not had as much time for flushing as a pre-LGM aquifers and also
which have not been subject to deep unsaturated oxidation. I acknowledge the author’s
difficulty in assigning clear names, but I think my modification may solve the problem. In
the attached document please see my modifications at lines:

Lines 43-45, 122-123, 127-128, 142, 258-259, 292-293

Also, please read the comments 2, 5, and 8.

I hope the authors will note that these clarifications do not take away the high relevance of
their study for the many deep pre-LGM Pleistocene aquifers! Their study is of course high
relevant for these – it just was not directly what was studied by the authors.

2. The authors should clarify the text at lines 137-142, which currently indicates that the

investigated pre-Holocene aquifer above 80 m depth was deposited before the LGM, while
their Fig. 2a shows that all sediment samples above 80 m depth post-date the LGM.

Please see comment 6.

3. The authors should rethink their “second explanation” for the triggering of As release. I

suggest they simply delete it, or that they provide more evidence for it to be a likely
scenario. Please see lines 268-277 and 284-286, and comment no. 9.

4.  Minors: I made a number of small modifications/clarifications and typo corrections while 
running through the text. Please see comment nos. 1, 3, 4, 7 and 10, and lines 41, 46, 47, 
52, 53, 64, 81-82, 83, 152, 168-169, 172, 183, 225, 228, 229, 230-231, 254, 265, 461, 767-
768, 770, and 794. 

 
 
Kind regards 
Soren