Distribution Characteristics and Ecological Risk Assessment of Pharmaceutical and Personal Care Products (PPCPs) in Different Water Sources, Soil Profiles and Rice Crops Under Rural Domestic Reclaimed Water Irrigations
, Caijie Yang 1, Lei Wang 1, Shizong Zheng 1, Ling Xiong 2, Peipei Kong 2,* and Jiafang Cai 1
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsI had the opportunity to review the manuscript titled "Distribution Characteristics and Ecological Risk Assessment of Pharmaceutical and Personal Care Products (PPCPs) in Soil and Rice Crops under Rural Domestic Reclaimed Water Irrigations." The primary objective of this study is to investigate the distribution patterns and ecological risks of PPCPs in soil and crops influenced by rural domestic reclaimed water (RDRW) irrigation. Overall, the topic is highly relevant, and the manuscript is well-structured and clearly written. I have outlined several comments and suggestions that require attention.
1. The number of rice samples and soil samples is not mentioned in the abstract.
2. The abstract does not clearly state the objectives of the research and the reader cannot easily understand what the main research questions are.
3. The abstract does not provide sufficient information about the methods used, which can lead to confusion in assessing the significance of the research.
4. The introduction does not refer to previous research, which may not provide the necessary context for the significance of the research.
5. The introduction does not clearly state the necessity and importance of the research.
6. In the conclusion section of the abstract, it is better to mention the selection of R3 water resources for direct agricultural irrigation.
7. The article must have a page number.
8. In Figure 1, the name of the region should be mentioned in the caption.
9. In Figures 4 and 5, the numbers are not clear enough.
10. In the caption of Table 1 and Figure 3, the abbreviation (PPCPs) should not be used. The full name should be mentioned.
11. The conclusion does not clearly and concisely summarize the key research findings and may confuse the reader in understanding the main message of the paper.
Author Response
- The number of rice samples and soil samples is not mentioned in the abstract.
Response: Five rice plant and soil samples were respectively taken from each treatment using the five-point sampling method.
- The abstract does not clearly state the objectives of the research and the reader cannot easily understand what the main research questions are.
Response: The objective of the research was to explore the distribution patterns in soil-crop system, further evaluating the ecological risks of PPCPs in soil and rice plants under the regulation of RDRW irrigation.
- The abstract does not provide sufficient information about the methods used, which can lead to confusion in assessing the significance of the research.
Response: The sample was pretreated using Solid phase Extraction (SPE) method. After pretreatment, PPCPs were quantitatively analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS).
- The introduction does not refer to previous research, which may not provide the necessary context for the significance of the research.
Response: The previous research about the effect of rural domestic reclaimed water irrigation on heavy metals was added, see the attached reference 9. If the effect of rural domestic reclaimed water irrigation on PPCPs in soil-crop system was also not significant, the reclaimed water is necessary for safe irrigation.
- The introduction does not clearly state the necessity and importance of the research.
Response:. If the impact of PPCPs in RDRW on soil-crop systems and ecological risks is also relatively small, it can be considered to replace river water for irrigation. And it was added in introduction.
- In the conclusion section of the abstract, it is better to mention the selection of R3 water resources for direct agricultural irrigation.
Response: R3 water resource was selected for direct agricultural irrigation in abstract section.
- The article must have a page number.
Response: Page numbers were added.
8.In Figure 1, the name of the region should be mentioned in the caption.
Response: The name of the region was added in caption.
- In Figures 4 and 5, the numbers are not clear enough.
Response: Figures 4 and 5 were improved.
- In the caption of Table 1 and Figure 3, the abbreviation (PPCPs) should not be used. The full name should be mentioned.
Response: The full name of PPCPs was mentioned in Table 2 to Table 5 and so does in Figure 3 to Figure 7.
- The conclusion does not clearly and concisely summarize the key research findings and may confuse the reader in understanding the main message of the paper.
Response: The conclusion section was reorganized to concisely summarize the key research findings.
Reviewer 2 Report
Comments and Suggestions for AuthorsDear Ms. Beryl Tang
Good evening. Thank you for providing me with the opportunity to review the article "Distribution characteristics and ecological risk assessment of pharmaceutical and personal care products (PPCPs) in soil and rice crops under rural domestic reclaimed water irrigations." The study seems interesting; however, I have some concerns regarding the methods used for data recording and risk calculation. Hence, this manuscript should be revised substantially based on comments mentioned below before being considered for publication.
General Comments:
1. A professional proofreader should check the English language of the whole manuscript.
2. How does the experiment maintain quality control?
3. The methodology section requires revision. The description of the sampling method seems confusing. What is the basis for selecting 22 PPCPs? The authors need to show details of the risk quotient calculation procedure. Who proposes this method? What is the unit of PNEC?
4. Did this study analyze basic irrigation water quality parameters? If so, adding all that data as supplementary material will help readers.
5. The authors need to strengthen the discussion section with relevant studies.
6. The conclusion reiterates the points made in the results. The conclusion should differ from the results and provide a precise and new summary based on the results and key findings of the study.
Specific Comments:
1. Title: It should be “Distribution characteristics and ecological risk assessment of pharmaceutical and personal care products (PPCPs) in different water sources, soil profiles and rice crops under rural domestic reclaimed water irrigations.”
2. Introduction: The first sentence requires reference(s). Last sentence: How does this study provide a scientific basis for selecting an appropriate irrigation method?
3. The authors mentioned in sub-head 2.2 that all indexes met the standards for irrigation water quality. What are the indexes considered in this study? Did this study analyze those parameters? The addition of all of that data as supplementary material will be helpful for readers.
4. Sub-head 2.3 (sampling method): How did the authors calculate a total of 40 irrigation water samples? Similarly, how do the numbers of soil and rice samples count as 288 and 72, respectively?
5. Sub-head 2.4 (Indicators and measurements): Language check for the last sentence of 2nd paragraph. Please use passive voice in the whole 3rd paragraph.
6. Sub-head 2.5 (Statistical analysis): What is a-1 (mg.kg-1.a-1)? How did the present study calculate Nj (irrigation water consumption) rate? Rice plant biomass data should be added as supplementary material.
7. The authors should use separate subheadings for the calculation of the bioconcentration factor and the risk quotient.
8. Avoid numbers at the start of a sentence [sub-heads 3.2 & 3.3—in the 2nd sentence, 15 should be replaced with "Fifteen (15)"].
9. sub-head 3.3: “The above analysis showed that….” should be replaced with “The above results demonstrated that….” Why are ACE and MIN lower in rice grains although their contents are higher in soils? Need to explain.
10. The last sentence in subhead 3.1 and the second sentence in subhead 4.2 seem contradictory. Please check and correct accordingly.
Comments on the Quality of English LanguageThe English could be improved to more clearly express the research.
Author Response
General Comments:
- A professional proofreader should check the English language of the whole manuscript.
Response: The English language was checked and improved.
- How does the experiment maintain quality control?
Response: The water quality was controlled by sewage treatment station, and only the sewage that meets the discharge standards will enter farmland.
- The methodology section requires revision. The description of the sampling method seems confusing. What is the basis for selecting 22 PPCPs? The authors need to show details of the risk quotient calculation procedure. Who proposes this method? What is the unit of PNEC?
Response: The methodology section was revised. The basis for selecting 22 PPCPs was because they are common pollutants in rural domestic sewage. The sampling method was improved and the method of the risk quotient calculation can see reference 20.
- Did this study analyze basic irrigation water quality parameters? If so, adding all that data as supplementary material will help readers.
Response: Yes. The irrigation water quality was monitored during the whole experimental period. See Table 3.
- The authors need to strengthen the discussion section with relevant studies.
Response: Some related articles were added while unnecessary articles were removed in discussion section.
- The conclusion reiterates the points made in the results. The conclusion should differ from the results and provide a precise and new summary based on the results and key findings of the study.
Response: The discussion section is reorganized.
Specific Comments:
- Title: It should be “Distribution characteristics and ecological risk assessment of pharmaceutical and personal care products (PPCPs) in different water sources, soil profiles and rice crops under rural domestic reclaimed water irrigations.”
Response: The title was revised as suggested.
- Introduction: The first sentence requires reference(s). Last sentence: How does this study provide a scientific basis for selecting an appropriate irrigation method?
Response: The reference was added. With study on the distribution patterns in soil-crop system, we can evaluate the ecological risks of PPCPs in soil and rice plants, therefore selecting the appropriate irrigation source and water level.
- The authors mentioned in sub-head 2.2 that all indexes met the standards for irrigation water quality. What are the indexes considered in this study? Did this study analyze those parameters? The addition of all of that data as supplementary material will be helpful for readers.
Response: The water quality indicators were added as shown in Table 3.
- Sub-head 2.3 (sampling method): How did the authors calculate a total of 40 irrigation water samples? Similarly, how do the numbers of soil and rice samples count as 288 and 72, respectively?
Response: The water sample collection includes four irrigation water sources and one groundwater sample, so a total of five water samples are taken each time. A total of 20 samples are taken during the five growth periods of rice, and a total of 40 samples will be collected in 2021 and 2022.
There are 4 soil layers for each sampling point, and 36 treatment each sampling time. In this study, we take samples before rice plantation and after the rice harvest, thus 288 soil samples in total.
5.Sub-head 2.4 (Indicators and measurements): Language check for the last sentence of 2nd paragraph. Please use passive voice in the whole 3rd paragraph.
Response: Language was checked and passive voice was used in the section.
6.Sub-head 2.5 (Statistical analysis): What is a-1 (mg.kg-1.a-1)? How did the present study calculate Nj (irrigation water consumption) rate? Rice plant biomass data should be added as supplementary material.
Response: The “a-1” was removed. Nj was the difference between irrigation water consumption and drainage. And the water consumption was sum of water evapotranspiration and leakage. Detailed calculation can refer to our former research in reference 19. The rice plant biomass data was added below formula (2).
7.The authors should use separate subheadings for the calculation of the bioconcentration factor and the risk quotient.
Response: Separate subheadings were added in section 2.5.
8.Avoid numbers at the start of a sentence [sub-heads 3.2 & 3.3—in the 2nd sentence, 15 should be replaced with "Fifteen (15)"].
Response: 15 was replaced with fifteen.
- sub-head 3.3: “The above analysis showed that….” should be replaced with “The above results demonstrated that….” Why are ACE and MIN lower in rice grains although their contents are higher in soils? Need to explain.
Response: Showed was replaced with demonstrated. The reason that ACE and MIN lower in rice grains although their contents are higher in soils might be ACE and MIN can not easy to move and enter the rice plants.
- The last sentence in subhead 3.1 and the second sentence in subhead 4.2 seem contradictory. Please check and correct accordingly.
Response: Section 3.1 mentioned the total concentration of PPCPs, while section 4.2 it was about risk quotient, and they were not the same concept. Therefore it was not conflict.
Comments on the Quality of English Language
The English could be improved to more clearly express the research.
Response: The language was improved carefully. Thank you for your kindly suggestions.
Reviewer 3 Report
Comments and Suggestions for AuthorsReview
“Distribution characteristics and ecological risk assessment of pharmaceutical and personal care products (PPCPs) in soil and rice crops under rural domestic reclaimed water irrigations”
The article concerns an extremely important topic in today's times, which is water pollution and the migration of PPCPs in the environment. The article is written in an interesting way, but it contains several significant gaps, the completion/explanation of which is crucial. They are described in detail in the comments.
General comments
The illustrations side of the article requires refinement. The illustrations are illegible. Improvement is necessary (this applies especially to figures no. 1, 4, 5).
Every abbreviation used in a scientific article (even the most obvious) must be explained when it first appears in the text. This procedure was not applied here for many abbreviations….EC50/LC50 NOEC/LOEC/EC10 CAS etc.
There is no line numbering, which makes writing reviews difficult.
Detailed comments
1. In the case of RDS and RDRW, the introduction does not discuss the issue related to bacteria, e.g. E. coli and possible disinfection. This issue should be included in the introduction, especially in the case of using sewage for growing edible plants.
2. The Introduction lacks information on applicable regulations and standards. A small expansion of this topic should be added. In addition, it is advisable to quote the requirements of class I A standard, e.g. in the form of a table.
3. Detailed geographical data concerning the experimental site are described, but without citing any literature source. Table 5 also seems to be incorrectly described - reference 1) does not appear anywhere in the table, and if the data is from a source, it should be indicated in the title.
4. Inaccurate description of treatment (please list the processes or devices used as primary and secondary treatment).
5. The origin of water/sewage directed to the ecological pond is unclear – please indicate in the text where it comes from – rainwater or rural domestic sewage?
6. It is also unclear what the Authors meant by writing about secondary effluent of RDS regeneration water… It is possible to guess, but it should be indicated more clearly – e.g. by supplementing the diagram (figure no. 2).
7. „The values of the upper and lower limit were water depth maintained by farmland, when it was lower than the lower limit of sewage, irrigated to the upper limit of sewage; when it was higher than upper limit of storage after rainfall, drained to upper limit of storage.”
The provision is not entirely clear and raises doubts, I propose rewording it and referring first to the upper limit and then to the lower limit, rather than combining them.
8. W1, W2, W3 – a brief explanation of what the water level regulations are is needed. The article may be interesting not only for farmers, but also for water and sewage specialists, and not everyone needs to know these regulations. This will increase the group of potential recipients.
9. While Figure 2 is clear and legible, the same cannot be said about Figure 1. Too many inaccuracies and doubts. The text does not mention the phrase "greenhouse barrel test area" even once... It is not discussed in any special way and called "field experimental plot" in this way. This is unacceptable.
10. Chapter 2.3
they were screened for 100 mesh – unit of size?
288 soil samples – lack of information of spatial structure of sampling? Only information about depth – to less
11. Chapter 2.4
“Finally, and conduct quantitative analysis.” Sounds strange…..sth lacks
EDTA McDonell reagent – is the name McDonell needed? What is the difference between EDTA reagent and EDTA McDonell reagent, please specify
12. Chapter 2.5.
Equations (1) and (2) – non-standard description – line by line suggestion for each component, it will be legible; furthermore, indexes unexplained – especially i (requires completion);
Equation (4) description – incomplete, what is AF and where in the formula does it appear?
Again, indexes i and j are unexplained;
13. Chapter 3.
Figure 3 – some of the hatchings, especially with patterns, raise doubts, require refinement – ​​with colors or signatures under each of the 4 samples of compounds found;
Figure 4 and 5 – completely illegible results – either we insert colors, or signatures or a table
Was a comparative soil test (without any irrigation) used?
„Bockers” ???
„SMA).” Does this sentence really end here? There is not even a line number on the side, so I suggest you look now for which line I mean…
“by IBU and CAF, accounting for 3.37%, 5.81%, 7.08%, 8.68%, 3.31%, 6.75%, 9.99% and 19.06%, respectively. “
Unclear - whether the data for R1, R2, R3 and CK for IBU is given first and then for CAF, or whether for IBU and CAF it is R1, then for R2; This should be stated unambiguously! And not for the reader to guess.
Comments for author File: 
Comments.pdf
Author Response
General comments
The illustrations side of the article requires refinement. The illustrations are illegible. Improvement is necessary (this applies especially to figures no. 1, 4, 5).
Response: Figures are improved carefully in the paper.
Every abbreviation used in a scientific article (even the most obvious) must be explained when it first appears in the text. This procedure was not applied here for many abbreviations….EC50/LC50 NOEC/LOEC/EC10 CAS etc.
Response: The abbreviations mentioned in the question were explained in the paper. CAS represented the unique numerical identification number of a substance.
There is no line numbering, which makes writing reviews difficult.
Response: Line numbers were added in the paper.
Detailed comments
- In the case of RDS and RDRW, the introduction does not discuss the issue related to bacteria, e.g. E. coli and possible disinfection. This issue should be included in the introduction, especially in the case of using sewage for growing edible plants.
Response: The related articles about bacteria and possible disinfection were added in introduction section.
- The Introduction lacks information on applicable regulations and standards. A small expansion of this topic should be added. In addition, it is advisable to quote the requirements of class I A standard, e.g. in the form of a table.
Response: There are detailed standards in section 2, see reference 17 and 18.
- Detailed geographical data concerning the experimental site are described, but without citing any literature source. Table 5 also seems to be incorrectly described - reference 1) does not appear anywhere in the table, and if the data is from a source, it should be indicated in the title.
Response: The cited literature was added in section 2.1. Reference 1 in table 5 was removed due to a typographical error.
- Inaccurate description of treatment (please list the processes or devices used as primary and secondary treatment).
Response: Primary treatment was conventional process and secondary treatment adopted anaerobic fermentation (A/O) with substrate biological filtration technology. Generally speaking, the concentration of pollutants in primary wastewater is higher than that in secondary wastewater.
5.The origin of water/sewage directed to the ecological pond is unclear – please indicate in the text where it comes from – rainwater or rural domestic sewage?
Response: The ecological pond water (R3) comes from the effluent of the secondary treatment water (R2).
6.It is also unclear what the Authors meant by writing about secondary effluent of RDS regeneration water… It is possible to guess, but it should be indicated more clearly – e.g. by supplementing the diagram (figure no. 2).
Response: The aim of secondary effluent of RDS was not only to compare the difference between the sewage and clean water, but also to compare water sources with different levels of pollution.
- „The values of the upper and lower limit were water depth maintained by farmland, when it was lower than the lower limit of sewage, irrigated to the upper limit of sewage; when it was higher than upper limit of storage after rainfall, drained to upper limit of storage.”
The provision is not entirely clear and raises doubts, I propose rewording it and referring first to the upper limit and then to the lower limit, rather than combining them.
Response: The expression was reorganized. See the notes under Table 1.
- W1, W2, W3 – a brief explanation of what the water level regulations are is needed. The article may be interesting not only for farmers, but also for water and sewage specialists, and not everyone needs to know these regulations. This will increase the group of potential recipients.
Response: The three water level regulations were explained in section 2.2 and Table 1.
9.While Figure 2 is clear and legible, the same cannot be said about Figure 1. Too many inaccuracies and doubts. The text does not mention the phrase "greenhouse barrel test area" even once... It is not discussed in any special way and called "field experimental plot" in this way. This is unacceptable.
Response: The irrelevant information in Figure 1 has been removed.
- Chapter 2.3
they were screened for 100 mesh – unit of size?
288 soil samples – lack of information of spatial structure of sampling? Only information about depth – to less
Response: Yes, mesh is the unit, and the larger the number, the finer the soil sample.
There are 4 soil layers for each sampling point, and 36 treatment each sampling time. In this study, we take samples before rice plantation and after the rice harvest, thus 288 soil samples in total.
- Chapter 2.4
“Finally, and conduct quantitative analysis.” Sounds strange…..sth lacks
EDTA McDonell reagent – is the name McDonell needed? What is the difference between EDTA reagent and EDTA McDonell reagent, please specify
Response: The sentence has been completed for “Finally, the quantitative analysis of pollutant concentration in water samples is conducted.”.
EDTA reagent and EDTA McDonell reagent are two different reagent.
- Chapter 2.5.
Equations (1) and (2) – non-standard description – line by line suggestion for each component, it will be legible; furthermore, indexes unexplained – especially i (requires completion);
Equation (4) description – incomplete, what is AF and where in the formula does it appear?
Again, indexes i and j are unexplained;
Response: Equations are revised as suggested. AF was removed. I represented different PPCPs, and j represented different irrigation water sources,
- Chapter 3.
Figure 3 – some of the hatchings, especially with patterns, raise doubts, require refinement – ​​with colors or signatures under each of the 4 samples of compounds found;
Figure 4 and 5 – completely illegible results – either we insert colors, or signatures or a table
Was a comparative soil test (without any irrigation) used?
„Bockers” ???
„SMA).” Does this sentence really end here? There is not even a line number on the side, so I suggest you look now for which line I mean…
“by IBU and CAF, accounting for 3.37%, 5.81%, 7.08%, 8.68%, 3.31%, 6.75%, 9.99% and 19.06%, respectively. “
Unclear - whether the data for R1, R2, R3 and CK for IBU is given first and then for CAF, or whether for IBU and CAF it is R1, then for R2; This should be stated unambiguously! And not for the reader to guess.
Response: Due to the large number of legends in Figures 3 to 5, which is 15, and there are only 12 colors in the software Origin used in this paper. Therefore, we were unable to create a color chart. We enlarged the image for a clearer view.
Bockers was replaced by blockers.
The expressions which seem confusing was improved. See the section 3.1.
