Vulnerability of Human Populations to Contamination from Petroleum Exploitation in the Napo River Basin: An Approach for Spatially Explicit Risk Assessment

Round 1

Reviewer 1 Report

Dear Authors

The presented  topic is interesting and worth attention. Modeling seems to be selected correctly. However, the results could be presented in a more accessible way.

The "Results" part should be reformatted. Having a separate section for "figures, tables and schemes" is unusual and rather unpractical.

The drawings in the version I got for review are not legible (poor resolution)

Please consider dividing fig 2 into two separate figures and extending their analysis in the text.

If the table 2 is only copied from the Rázuri publication, it may not be necessary to include it in the manuscript.

Fig 2b descriptions are in Spanish.

A serious problem is also the lack of access to, for example, original data on PAHs contamination. Therefore, it is difficult to assess the obtained and presented results. 

 

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

Dear Authors

In my opinion the theme of the article is innovate and interesting for the readers of the journal.

The manuscript under revision is well structured, the language is correct, and the title and abstract clearly describe the content of the manuscript.

However, I have some points to the authors:

1) state of the art is missing in the introduction section, request the author to revised in support with recent work (Kindly see the attached file).

2) abbreviation need to be defined before using, authors need to be checked thoroughly 

3) conclusion needs to be re-written followed by recommendation of future study 

Best regards

Comments for author File: Comments.pdf

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 3 Report

Evaluation and specific comments

Authors present study aiming to develop a special model of contamination risk and to determine the vulnerability of local residents to contamination in the area of petroleum exploitation in the Napo River, Ecuador. The approach linking the contamination, risk and human health parameters (blood analysis) is interesting and has potential to be useful for the wider scientific audience, however, in its current form the manuscript need significant reworking and improvement (see comments below).

Lines 14-15: Reviewer is confused on the subject of this study - polycyclic aromatic hydrocarbons are only mentioned here and in the Introduction (line 50). While in the “Results” total petroleum (TPH in Figure 2 and Table 3) or oil  contamination (e.g. line 400) were considered – please carefully check the manuscript and correct.

Lines 96-101: the research hypothesis is missing

Subchapters in the methodological section should be numerated

Lines 104-115: description of the study area is too brief to understand the reason for this kind of assessment. Firstly, it is unclear for which contaminants modelling was performed (in the Introduction only PAHs were characterized, but in the Figure 2 results for TPH are presented). Secondly, there is a lack of information how many sampling/monitoring points were taken into account and what was a control in this study. Thirdly, which contaminants and by which method were analyzed? Finally, the potential sources of contaminants should be identified and described in this subchapter.

Line 110: please insert Figure 1 here (it is currently in the Results chapter)

Lines 134-135: please transfer here Table 1 from results

Lines 157-158: Table 2 should be inserted here (currently in the Results)

Line 190 and line 195: authors refer in the methodological part to the Figure 2, but according to reviewer it presents the results of spatial model of contamination risk and should be given and described in subchapter 3.1 (Results)

Line 205: the following sentence “ts is refer to the total samples take, in this study six samples” is not consistent with previous given in line 194 where authors wrote that contamination data were detected in 27 monitoring points. Does it mean that real contamination was assessed based on only 6 samples? Please check, clarify and correct.

Lines 208-218: this chapter is focused on the contamination risk categorization (assessment), but not on “Vulnerability of human populations”. Please change the subtitle to be consistent with the text.

Lines 215-216: what criteria was used for risk categorization to low, medium and high risk? - please include appropriate reference

Line 224: the confounding factors and all sources of pollution should be mentioned and described in the subchapter “Study area”

Line 227: “we selected 26 localities with different level of contamination” – it is inconsistent with data given in line 194 (27 points) and line 205 (6 samples) – please clarify

Lines 227-229: please clarify – Were these localities selected based on the contamination level (give precise values for specific contaminants) or on the predicted risk level? What pollutants were taken into account?

Line262: it should be “STGO and STGP”

Lines 236-262: An analysis of blood and biochemical parameters was described in these paragraphs. However, I wonder how changes in white blood cells, CRP, AST, ALT describe the human vulnerability to the presence of contaminants. Abnormal levels of these parameters are a result of other factors, e.g. incorrect diet, exposure to the air contaminants, pesticides (in the case of croplands) or the occurrence of diseases. Authors not mentioned that such factors were analyzed for population of inhabitants from which blood samples were taken. Additional factor, which should be considered is a time of human living (time of exposure) in the study area in the vicinity of the petroleum industry. It would be very valuable to determine the level of main contaminants in blood samples.

Lines 282-286: the results of spatial model and its validation should be presented here (instead in the methodological part)

Lines 285-286: I cannot find the results of correlation analysis

Line 292: please insert Figure 3 here (currently in subchapter 3.3.)

Line 308: “a percentage between 20 to 30% of total area” – I cannot see these values in Figure 4

Line 309: it is not necessary to give all tables and Figures in separate chapter. Reviewer recommends to transfer them to methodological or Result parts, when they are first mentioned.

Comment to all Figures: each title should be under (not above the Figure); the quality (readability) of Figure 2 and 3 should be improved – the font size is too small, the legend should be in English.

Table 1 and Table 2: should be transferred to the “Materials and methods”

Table 3: results presented here were not described in the text; Authors did not mention in “Materials and methods” that TPH was determined in this study in water and sediment samples – it is somehow confusing for the reader

Lines 364-383: this paragraph refers to the results not to the discussion

Line 365: was spatial model developed for contaminants in “water and land surface” or “in water and sediment samples” (as was given in Table 3)

Line 372-373: the concentration of contaminants in the study are was not shown in the manuscript

Lines393-395: Are the Authors sure that such a small difference (0.10 and 0.20 times) in the incidence of inflammation between localities with high-risk and low-risk is not accidental and is statistically significant to draw any conclusions?

References - should be prepared according to journal guideline

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The text after corrections is fine and can be published 

Reviewer 3 Report

I read the revised version of the manuscript carefully and found that the authors made a great effort and reorganized and improved it significantly. All my previous comments and suggestions were taken into account both in the text and in response to the review.  I stand by my first opinion that this manuscript may be of use to a wider scientific community, and thanks to the corrections and explanations introduced, it is worth publishing in its present form.