Atmospheric Concentrations and Health Implications of PAHs, PCBs and PCDD/Fs in the Vicinity of a Heavily Industrialized Site in Greece
Round 1
Reviewer 1 Report
The manuscript “Atmospheric concentrations and health implications of PAHs, PCBs and PCDD/Fs in the vicinity of a heavily industrialized site in Greece” explores, the presence in the particulate phase of atmospheric air of different pollutants of high concern, i.e. PAHs, PCBs and PCDD/Fs.
The interest of this research is clear and completely justified in terms of obtaining vital information for the occurrence of these pollutants in the area under study and the health implications derived. Furthermore, it is also important in terms of gaining knowledge on the distribution and environmental behavior and fate of these chemicals. Having said that, I take some important issues with the current form of this manuscript:
- The most important one is the fact that the authors measured the content of all study pollutants in the PARTICULATE PHASE of the air sampled. This is absolutely vital, and, unfortunately overlooked by the authors throughout the whole manuscript. PCBs and PCDD/Fs are mostly present in the GAS PHASE with a minor presence in the PARTICULATE PHASE. This, however, has not prevented the authors from establishing comparisons with many other studies where either only GAS PHASE has been analyzed (e.g. references 34, 53, 61…) or Gas+Particulate phases have been analyzed (e.g. 51, 54, 59, 60…). This is simply wrong, as it is, in my opinion, the use of most of the info collected in Table 5. The authors should not be comparing results stemming from different phases and/or combination of them, especially, as I already stated the presence of PCBs and PCDD/Fs tend to be much higher in the gas phase. This, also, has its repercussion in the health implications the authors derived from their research and should be taken into account to explicitly give perspective to their results.
More specific comments I have:
- According to my calculations volumes of approximately 55 m3 have been taken. This is a value pretty low in my experience in order to measure PCDD/Fs in the atmosphere. Is there any explanation/reason as to why not greater volumes were taken?
- Information about commercial providers of all analytical standards is missing (section 2.2. Materials)
- The Map in Figure 1 should include some coordinates in order to make it more standardly legible.
- The authors indicate that each filter’s half was analyzed in triplicate. I do not understand this well. Does it mean that each half was further divided into three equal pieces? If so, have they evaluated the impact that could have in their LODs?
- As for PAHs, given the very very low levels the authors report, I suggest they express the results in pg/ m3 instead of ng/m3.
- Lines 169-173. I found really odd that using the DFS software for the determination of PCDD/Fs and PCBs, the authors came up with a generic LOQ of 0.1 pg/sample for all PCDD/F and noPCB congeners. What is the explanation for that? Given that the LOQs are used for the upper bound approach, the calculation of an LOD for each congener in each sample is critical, having a direct impact on the final PCDD/F concentrations and therefore on the calculated TEQs.
- The authors explained that their data do not follow normality. In consequence, I think they should drop their use of average data discussed throughout the manuscript while adopting the use of median values instead (currently median values can be found only in the table).
Furthermore, as far as I know the assumption of normality is required when performing a PCA. Have the authors considered that? There exist non-parametric PCAs that can be used as it is the case of categorical PCAs.
- Line 307: should read Figure 2
- The English is totally understandable, but there are a handful of mistakes, for instance when saying “The PCDD/Fs and dlPCBs results…(line297)” Please note that it should read “The PCDD/F and dlPCB results…” This sort of mistake is pretty common throughout the manuscript; please try to correct them.
Author Response
Manuscript No: applsci-1003559
Title: Atmospheric concentrations and health implications of PAHs, PCBs and PCDD/Fs in the vicinity of a heavily industrialized site in Greece
Response to reviewers’ comments
We would like to thank the reviewers for their valuable comments and suggestions. Continuing, we enclose the responses to all the reviewers’ comments on the manuscript. (The lines are referred to the manuscript, highlighted with track changes)
Reviewer 1
General Comment
Q1 The most important one is the fact that the authors measured the content of all study pollutants in the PARTICULATE PHASE of the air sampled. This is absolutely vital, and, unfortunately overlooked by the authors throughout the whole manuscript. PCBs and PCDD/Fs are mostly present in the GAS PHASE with a minor presence in the PARTICULATE PHASE
R1 Very important observation. In the revised manuscript we have added appropriate details about the sampling in order to be clear that we refer to Particulate phase levels of POPs (Please see lines 21 in Abstract, lines 270, 273-276, 277, 283-284, 297, 301-302, 304 in 3.1.2 section and lines 385, 388-389, 391, 395.
According to literature some of PCDD/Fs and in particular PCBs are mostly present in gas phase indeed, but there are also studies only in particulate phase and some of them argue that with the increase of chlorination PCDDF/s tend to present more in particulate phase. (Please see lines 74-79 in introduction for references)
The choice we made to study particulate phase, was in order to combine POPs’ impact in already legislated PM10.
Q2 This, however, has not prevented the authors from establishing comparisons with many other studies where either only GAS PHASE has been analyzed (e.g. references 34, 53, 61…) or Gas+Particulate phases have been analyzed (e.g. 51, 54, 59, 60…). This is simply wrong, as it is, in my opinion, the use of most of the info collected in Table 5. The authors should not be comparing results stemming from different phases and/or combination of them, especially, as I already stated the presence of PCBs and PCDD/Fs tend to be much higher in the gas phase.
R2 Correct observation. Our scope is to present the impact of the most industrialized area of Greece in atmospheric degradation and as a result to human health of the citizens only a few km from Athens. In that perspective we emphasize in the comparison of different sampling sites and not to the sampling procedure. (Please see lines 279-281) We also believe that is important to compare with other studies having a briefing literature review as in Table 5 even if the sampling procedure is not the same. However, we have improve Table 5 adding if the sampling was carried out in particulate or gas phase and in any comparison with available literature we have added where the sampling was made. (Table 5 and lines as in Q1)
Q3 This, also, has its repercussion in the health implications the authors derived from their research and should be taken into account to explicitly give perspective to their results.
R3 Correct. Comments about underestimation in health implications have been added in revised manuscript (Please see lines 294-296 and 472-475)
More Specific Comments
Q4 According to my calculations volumes of approximately 55 m3 have been taken. This is a value pretty low in my experience in order to measure PCDD/Fs in the atmosphere. Is there any explanation/reason as to why not greater volumes were taken?
R4 In this study we try to compare POPs’ levels and health implications in legislated PM10 and thus our sampling procedure was carried out according to EN 12341. Due to very sensitive techniques used for the analysis we were able to quantify samples even in pg/sample and according to the results for most compounds the values were over Limit of Quantitation.
Q5 Information about commercial providers of all analytical standards is missing (section 2.2. Materials)
R5 Correct. Information added (Please see lines 113-114)
Q6 The Map in Figure 1 should include some coordinates in order to make it more standardly legible.
R6 Figure 1 was appropriately modified according to reviewer’s suggestion (Please see lines 96-97).
Q7 The authors indicate that each filter’s half was analyzed in triplicate. I do not understand this well. Does it mean that each half was further divided into three equal pieces? If so, have they evaluated the impact that could have in their LODs?
R7 We would like to clarify that the extraction step is repeated 3 times and not each filter’s half.
Q8 As for PAHs, given the very very low levels the authors report, I suggest they express the results in pg/ m3 instead of ng/m3.
R8 Very good observation. The reason that we have chosen ng/m3 instead of pg/m3 for PAHs results is to be easily compared with other studies in section 3.1.1. In studies with even lower concentrations they also have expressed their results in ng/m3 and this is why we have made this choise.
Q9 Lines 169-173. I found really odd that using the DFS software for the determination of PCDD/Fs and PCBs, the authors came up with a generic LOQ of 0.1 pg/sample for all PCDD/F and noPCB congeners. What is the explanation for that? Given that the LOQs are used for the upper bound approach, the calculation of an LOD for each congener in each sample is critical, having a direct impact on the final PCDD/F concentrations and therefore on the calculated TEQs.
R9 Good observation. More detailed information about the calculation of LOQs and LODs of the method for the determination of PCDDF/s and PCBs have been added (Please see lines 181-185, 188-192). The LOQ of each congener has been used for the calculations to investigate the worst-case scenario of exposure (upperbound level).
Q10 The authors explained that their data do not follow normality. In consequence, I think they should drop their use of average data discussed throughout the manuscript while adopting the use of median values instead (currently median values can be found only in the table).
R10 Correct. The expression of the results was appropriately modified and mean values have been replaced by median values in accordance with reviewer’s suggestion.
Q11 Furthermore, as far as I know the assumption of normality is required when performing a PCA. Have the authors considered that? There exist non-parametric PCAs that can be used as it is the case of categorical PCAs.
R11 Correct observation. We explain that PCA has been used in many environmental studies for investigation of possible associations among pollutants that do not follow normal distribution (Please see lines 192-197).
Q12 Line 307: should read Figure 2
R12 Correct. The caption of Figure 2 has been revised appropriately (Line 328).
Q13 The English is totally understandable, but there are a handful of mistakes, for instance when saying “The PCDD/Fs and dlPCBs results…(line297)” Please note that it should read “The PCDD/F and dlPCB results…” This sort of mistake is pretty common throughout the manuscript; please try to correct them.
R13. We apologize for that mistake, very good observation. This grammatical mistake has been corrected in many sentences. (Please see lines 263, 265, 328, 328, 343-344, 353, 379, 384, 399).
Reviewer 2 Report
The paper presented is interested and well organized and I recommend it for publication after minor revision. My comments:
∑BAPTEQ is not clear how you calculate it. Maybe there is a missing ∑ in lines 189 and 190? If not, please, state how do you obtain it.
line 336 - I would not say PCDD/FS are more toxic during cold months but that they pose a higher risk to health during cold months due to their higher concentrations.
Which one is D/R ratio?
English:
I've observed repeated problems with passive sentences throughout the manuscript. Some of them:
Line 44. could also be emitted
Line 67. IARC's (the I seems like a 1)
Line 79. Final "s" in peoples is not necessary
Line 182. Auxiliary verb is missing (was)
Line 196 "be"
Line 256 to 260 - please revise grammar and style
Line 393 - "were" influenced
Author Response
Manuscript No: applsci-1003559
Title: Atmospheric concentrations and health implications of PAHs, PCBs and PCDD/Fs in the vicinity of a heavily industrialized site in Greece
Response to reviewers’ comments
We would like to thank the reviewers for their valuable comments and suggestions. Continuing, we enclose the responses to all the reviewers’ comments on the manuscript. (The lines are referred to the manuscript, highlighted with track changes)
Reviewer 2
General
Q1 ∑BAPTEQ is not clear how you calculate it. Maybe there is a missing ∑ in lines 189 and 190? If not, please, state how do you obtain it.
R1 Thank you for your comment. ΣBAPTEQ and ΣBAPMEQ equations have been appropriately modified (Please see lines 203-209).
Q2 line 336 - I would not say PCDD/FS are more toxic during cold months but that they pose a higher risk to health during cold months due to their higher concentrations.
R2 Thank you for your suggestion. The revised manuscript has been corrected (Please see lines 359-360)
Q3 Which one is D/R ratio?
R3 Correct. D/F replace D/R ratio (Line 417).
Q4 English:
I've observed repeated problems with passive sentences throughout the manuscript. Some of them:
Line 44. could also be emitted
Line 67. IARC's (the I seems like a 1)
Line 79. Final "s" in peoples is not necessary
Line 182. Auxiliary verb is missing (was)
Line 196 "be"
Line 393 - "were" influenced
R4 We apologize for these grammar mistakes. We have revised appropriately the manuscript (Please see lines 46, 69, 86, 191, 210, 419).
Q5 Line 256 to 260 - please revise grammar and style
R5 Correct. These sentences have been rephrased (Please see lines 270-275).
Author Response File: 
Author Response.docx
