Comprehensive Evaluation of Pollution Status and Health Risk Assessment of Water Bodies in Different Reaches of the Shaying River
Round 1
Reviewer 1 Report (Previous Reviewer 1)
Comments and Suggestions for AuthorsReviewer comments
The study has significantly improved and now presents a cleaner narrative and clearer figures, but its scientific advance remains modest. It still relies on a single late-autumn snapshot (November 2019) of just 33 sites to characterise water chemistry, metal burdens, and ecological-plus-human risks in the 1 000 km² Shaying River catchment. Earlier investigations have already mapped eutrophication hotspots, quantified seasonal nutrient loading, and identified sediment-borne metals in this river. The current manuscript adopts familiar tool-sets—five-parameter Water-Quality Index (WQI), PCA, Hakanson’s ecological-risk index, and a dermal-only US-EPA health-risk screen—but does not expand temporal coverage, introduce novel tracers, or explore new exposure pathways. Consequently, the study reads as a useful local status report rather than a step-change in theory or management practice.
All conclusions are extrapolated from a single November-2019 campaign; no wet-season or inter-annual data are provided. Because diffuse nutrient inputs and runoff peaks in the Huai basin occur during summer monsoon months, statements such as “overall, the river was moderately polluted” should be restricted to late-autumn conditions or fortified with long-term records from provincial monitoring stations.
The WQI still uses only five variables—DO, COD\_Mn, NH₃-N, TP and pH—while the study actually measures thirteen parameters, including NO₃⁻, TN, TDS, salinity and hardness that later dominate the PCA discussion. Excluding these constituents risks under-weighting salinisation and nitrate pollution and weakens any cross-comparison with other Huai-River studies that apply a full-suite WQI. Either expand the index to incorporate all measured variables (with justified weights) or defend, with literature evidence, why the reduced set captures ≥90 % of variance in regional water quality.
The manuscript now reports a KMO of 0.698 and Bartlett p < 0.001 and extracts five rotated components that together explain 87 % of the variance. However, the sample-to-variable ratio remains < 3:1 (33 samples vs 13 variables), which can yield unstable loadings. A scree or parallel-analysis plot and a short Monte-Carlo check would help demonstrate that retaining five PCs avoids over-fitting while still being interpretable.
The text continues to promise “eight heavy metals,” yet only six—Cr, As, Cd, Sb, Pb and Hg—appear in detection-limit tables. If Cu and Ni (for instance) were analysed but below detection, their MDLs and recovery statistics should be reported; otherwise, the manuscript should consistently refer to a six-metal study. On the positive side, recoveries (85-115 %) and RSD (±5 %) are now given, but the authors should also state how many data points were removed as box-plot outliers and confirm that ion-balance errors for major ions did not exceed ±5 %.
The Results state that most sites are only moderately polluted (median WQI ≈ 71) and that ecological risk is largely moderate, yet the Discussion still labels metal pollution “serious,” while human HI and CRI values remain below threshold. Language should be toned down or reconciled—e.g., “ecologically moderate but currently posing limited human risk, though cumulative effects warrant vigilance.” The six-fold higher CRI for children relative to adults is particularly policy-relevant and deserves mention in both Abstract and Conclusions.
The revision has improved English style, added statistical detail, and clarified some methods, but crucial scientific limitations persist. Before the paper can be considered for publication, the authors should (1) confine conclusions to late-autumn conditions or add wet-season/long-term data; (2) broaden or robustly justify the five-parameter WQI; (3) correct the “eight-metal” inconsistency and report full QA/QC; (4) include ingestion pathways in the health-risk model or defend their omission empirically; and (5) supply evidence that the five-component PCA is statistically stable. Addressing these points will transform the manuscript from a descriptive survey into a defensible, broadly useful contribution.
Author Response
Dear Editor and Reviewers:
Thank you for taking the time to review our paper and giving us the opportunity to revise it. We have made corresponding revisions to the paper in response to your valuable suggestions and comments. The revised parts are shown in the manuscript using the revision mode. At the same time, we would like to answer your questions one by one and provide responses to the revisions (in blue font) here:
- Confine conclusions to late-autumn conditions or add wet-season/long-term data.
Answer: Thank you for your advice. We have clearly limited all the results and conclusions of the manuscript regarding the pollution situation and risk assessment to the late-autumn period.
- Broaden or robustly justify the five-parameter WQI.
Answer: Thank you for your advice. When conducting the research, we measured 13 water physicochemical parameters. However, when calculating the WQI, we adopted five relatively important parameters in the river water quality evaluation standards issued by the State Environmental Protection Administration of China. The main reason is that our research was limited to the late autumn period. Parameters such as water temperature, turbidity and electrical conductivity, which also play important roles in water quality evaluation, have relatively small differences in different study areas.
- Correct the “eight-metal” inconsistency and report full QA/QC.
Answer: Thank you for your advice. We have corrected the “eight-metal” and changed it to “six-metal”. (Line 170 of the revised manuscript). Meanwhile, we uploaded a quality assurance and quality control report.
- Include ingestion pathways in the health-risk model or defend their omission empirically.
Answer: Thank you for your advice. We have added the ingestion pathways to the health risk model. Meanwhile, revisions have been made in both the material methods section and the result discussion section.
- Supply evidence that the five-component PCA is statistically stable.
Answer: Thank you for your advice. We have conducted principal component analysis in SPSS 25.0 and generated Scree Plot. It can be seen from the results of the Scree Plot that the slope of the curve significantly slows down after the sixth factor. According to the Kaiser criterion (eigenvalue >1), the eigenvalues of the first five principal components are all greater than 1, and the cumulative contribution rate reaches 86.997% (>85%), which can fully explain the vast majority of the information of the original variables. Therefore, the five principal components selected in the study can achieve a balance between dimension reduction optimization and information retention.
Author Response File: 
Author Response.pdf
Reviewer 2 Report (Previous Reviewer 2)
Comments and Suggestions for AuthorsAfter reviewing the modifications made by the authors following the first revision, in my opinion, the article can be accepted for publication.
The authors have worked on addressing the issues raised in the first review. While some points could benefit from more in-depth explanations, it can be said that the article meets a sufficient standard of quality for publication.
Author Response
Dear Editor and Reviewers:
Thank you for taking the time to review our paper and giving us the opportunity to revise it. We have made corresponding revisions to the paper in response to another reviewer suggestions and comments. The revised parts are shown in the manuscript using the revision mode. We look forward to your review and guidance.
- Confine conclusions to late-autumn conditions or add wet-season/long-term data.
Answer: Thank you for your advice. We have clearly limited all the results and conclusions of the manuscript regarding the pollution situation and risk assessment to the late-autumn period.
- Broaden or robustly justify the five-parameter WQI.
Answer: Thank you for your advice. When conducting the research, we measured 13 water physicochemical parameters. However, when calculating the WQI, we adopted five relatively important parameters in the river water quality evaluation standards issued by the State Environmental Protection Administration of China. The main reason is that our research was limited to the late autumn period. Parameters such as water temperature, turbidity and electrical conductivity, which also play important roles in water quality evaluation, have relatively small differences in different study areas. 1
- Correct the “eight-metal” inconsistency and report full QA/QC.
Answer: Thank you for your advice. We have corrected the “eight-metal” and changed it to “six-metal”. (Line 170 of the revised manuscript). Meanwhile, we uploaded a quality assurance and quality control report.
- Include ingestion pathways in the health-risk model or defend their omission empirically.
Answer: Thank you for your advice. We have added the ingestion pathways to the health risk model. Meanwhile, revisions have been made in both the material methods section and the result discussion section.
- Supply evidence that the five-component PCA is statistically stable.
Answer: Thank you for your advice. We have conducted principal component analysis in SPSS 25.0 and generated Scree Plot. It can be seen from the results of the Scree Plot that the slope of the curve significantly slows down after the sixth factor. According to the Kaiser criterion (eigenvalue >1), the eigenvalues of the first five principal components are all greater than 1, and the cumulative contribution rate reaches 86.997% (>85%), which can fully explain the vast majority of the information of the original variables. Therefore, the five principal components selected in the study can achieve a balance between dimension reduction optimization and information retention.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report (Previous Reviewer 1)
Comments and Suggestions for AuthorsThe authors have made all necessary revisions. The article is acceptable for publication.
This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe manuscript presents a broad and environmentally relevant analysis of the Shaying River using Water Quality Index (WQI), Principal Component Analysis (PCA), Potential Ecological Risk Index (RI), and Human Health Risk Assessment (HHRA). These methods are standard for riverine environmental evaluations, and the authors apply them across a large spatial range with various land use types (mountain, agricultural, urban). However, while the study is comprehensive in data collection, its scientific novelty, depth of analysis, and interpretive discussion are limited. The work remains largely descriptive, and more robust statistical validation, spatial analysis, and theoretical contributions are needed.
The manuscript is appropriate for a journal like Water in topic but not yet in execution. Major improvements are required in the analytical framework, presentation quality, and English language usage.
Comments for author File: Comments.pdf
Grammar and syntax errors are frequent (e.g., plural/singular mismatches). Professional English editing is strongly recommended.
Author Response
Please see the attached file.
Author Response File: Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsReview of the manuscript: Comprehensive Evaluation of Pollution Status and Health Risk Assessment of Water Bodies in Different Reaches of the Shaying River
This manuscript presents a study aimed at analyzing water quality data collected from various sections of the Shaying River Basin. While the analysis may hold some value at a local scale, the scientific contribution is limited and, in its current form, does not meet the standards required for publication in a high-impact journal. The following points summarize the main concerns:
- The study does not present any novel scientific contributions, as all the methods applied are well-established and widely used.
- The methodology section lacks sufficient detail, particularly in explaining how certain data points and formula parameters were estimated.
- There is an absence of explanation or justification for some of the key findings.
- Most of the conclusions drawn are rather trivial; for instance, the observation that pollution levels are higher near discharge points is expected and lacks analytical depth.
Given these limitations, I believe this manuscript would be more appropriate for presentation at a conference or publication in a lower-impact journal.
Additional Comments:
Regarding the Water Quality Index (WQI):
- The manuscript does not include appropriate references for the WQI methodology.
- There is no clarification on how the weights for each contaminant were determined. For example, the scoring for dissolved oxygen (DO) is questionable: a concentration above 6.5 mg/L receives a score of 80, even though under natural conditions the concentration should be around 12 mg/L.
Calculation of the Potential Ecological Risk Index:
- The toxicity response factors used in the calculation are not explained or justified.
Health Risk Assessment: The authors state:
“However, ethnic differences in different regions make the exposure parameters used in the health risk assessment very different. However, if the original data from the United States are directly used for the health risk assessment of China population, the results obtained will be somewhat different from the actual health status of China residents.”
This claim should be supported with appropriate references or further elaborated to clarify the basis and implications of these regional differences in exposure parameters.
Chronic Daily Intake (CDI):
- The explanation of the formula includes the term ABS, which does not appear in the formula itself. It is unclear how each term was defined or sourced.
Carcinogenic Risk Index (CRI):
- The authors state that a CRI value below 10⁻⁶ indicates no carcinogenic risk. A proper reference should be provided to support this threshold.
Discussion Section:
- The discussion includes speculative explanations for some of the observed results without presenting supporting evidence. For example, the rationale given for the higher potential ecological risk of Hg in sediments from the agricultural area is not substantiated and appears questionable.
Author Response
Please see the attached file.
Author Response File: Author Response.pdf
