Groundwater Quality and Associated Human Health Risk in a Typical Basin of the Eastern Chinese Loess Plateau
Round 1
Reviewer 1 Report
The purpose of the manuscript “water-1674372” is to evaluate the quality and human health risks of groundwater in the Linfen Basin, a typical basin of the Eastern Chinese Loess Plateau.
The paper appears well-structured; however, some sections must be improved. Therefore, I believe
the manuscript should be published only after major revision.
Comments
The introduction does not take into account many general factors responsible for mineralization, water pollution and water treatment. Read and add the following books and work in the references:
Appelo, C.A.J. and Postma, D., 2004. Geochemistry, groundwater and pollution. CRC press.
Langmuir, D., 1997. Aqueous environmental geochemistry (No. 551.48 L3.).
Apollaro, C., Marini, L. and De Rosa, R., 2007. Use of reaction path modeling to predict the chemistry of stream water and groundwater: a case study from the Fiume Grande valley (Calabria, Italy). Environmental geology, 51(7), pp.1133-1145.
Fuoco, I., De Rosa, R., Barca, D., Figoli, A., Gabriele, B. and Apollaro, C., 2022. Arsenic polluted waters: Application of geochemical modelling as a tool to understand the release and fate of the pollutant in crystalline aquifers. Journal of Environmental Management, 301, p.113796.
Fuoco I., Figoli A., Criscuoli A., Brozzo G., De Rosa R., Gabriele B., Apollaro C. (2020) Geochemical modeling of chromium release in natural waters and treatment by RO/NF membrane processes. Chemosphere, 254, art. no. 126696. DOI: 10.1016/j.chemosphere.2020.126696
Is completely absent a geological description. Furthermore should be added a geological map with highlighted the major tectonic features
It is not reported any data regarding analysis accuracy and precision. It is recommended to add this information
A chemical classification of the water should be added using a Piper diagram and a TIS
furthermore, to better comment on the statistical parameters, box-plots should be used
Discussions and conclusions need to be rewritten taking into account previous comments
Recommended works must be added in the bibliography
Author Response
Dear Reviewer,
Thank you for your letter and for the reviewer’s comments concerning our manuscript entitled “Groundwater Quality and Associated Human Health Risk in a Typical Basin of the Eastern Chinese Loess Plateau” (ID: water-1674372). These comments are all valuable and helpful for improving our paper. We have tried our best to revise our manuscript according to the comments. Revised portion are marked up using the “Track Changes” function. The followings are the responses to the reviewer.
Point 1: The introduction does not take into account many general factors responsible for mineralization, water pollution and water treatment. Read and add the following books and work in the references:
Appelo, C.A.J. and Postma, D., 2004. Geochemistry, groundwater and pollution. CRC press.
Langmuir, D., 1997. Aqueous environmental geochemistry (No. 551.48 L3.).
Apollaro, C., Marini, L. and De Rosa, R., 2007. Use of reaction path modeling to predict the chemistry of stream water and groundwater: a case study from the Fiume Grande valley (Calabria, Italy). Environmental geology, 51(7), pp.1133-1145.
Fuoco, I., De Rosa, R., Barca, D., Figoli, A., Gabriele, B. and Apollaro, C., 2022. Arsenic polluted waters: Application of geochemical modelling as a tool to understand the release and fate of the pollutant in crystalline aquifers. Journal of Environmental Management, 301, p.113796.
Fuoco I., Figoli A., Criscuoli A., Brozzo G., De Rosa R., Gabriele B., Apollaro C. (2020) Geochemical modeling of chromium release in natural waters and treatment by RO/NF membrane processes. Chemosphere, 254, art. no. 126696. DOI: 10.1016/j.chemosphere.2020.126696
Response 1: Considering the reviewer’s suggestion, we added the sentence “Anthropogenic sources of groundwater pollutants include fertilization, livestock waste, domestic sewage, landfill, metal industry, mining and other industrial activities. Processes controlling concentrations of physicochemical parameters in groundwater are mainly the mineral dissolution, sorption and desorption processes, ion exchange, reduction and oxidation processes, and chemical weathering”(Lines 45-49) in the Introduction.
Point 2: Is completely absent a geological description. Furthermore should be added a geological map with highlighted the major tectonic features
Response 2: Thank you for your suggestion, we full agree with your suggestion. We added detailed geological and hydrogeological conditions of the area (Lines 127-155). A hydrogeological map with major tectonic features has also been added (Figure 1). Please see the Methods and materials 2.1 for detailed modifications.
Point 3: It is not reported any data regarding analysis accuracy and precision. It is recommended to add this information
Response 3: Thank you for your suggestion. We added analysis accuracy and precision in Materials and Methods 2.2 (Lines 183-185):
Lines 183-185: During the analysis, distilled water and replicates were introduced to ensure the reliability of the results. The replicates had a relative errors within ±5%, indicating acceptable analytical accuracy.
Point 4: A chemical classification of the water should be added using a Piper diagram and a TIS
Response 4: The purpose of this study was mainly to evaluate the pollution of groundwater in the study area and its safety as a drinking water source. Therefore, the selection and analysis of water quality parameters were carried out according to Chinese national standard for groundwater quality, and cations such as Ca2+, Mg2+, K+ and Na+ were not analyzed. The research team has investigated the spatiotemporal variations of chemical composition of groundwater in the study area. In the slowflow season, groundwater mainly belong to the (SO42--Ca2+) type , the (HCO3--Ca2+-Na+) type and the (HCO3--Mg2+-Na+) type. In the quickflow season, groundwater dominated by the (HCO3--Ca2+-Na+) type and the (HCO3-- SO42--Ca2+-Na+) type (https://doi.org/10.1007/s12145-021-00696-1).
Point 5: Furthermore, to better comment on the statistical parameters, box-plots should be used
Response 5: Considering the reviewer’s suggestion, we drew the box-plot of the measured data. However, in this study, the box-plot can not well reflect the distribution characteristics of the data. The relatively small amount of data may be one reason. In addition, pH and other water quality parameters have different dimensions, and the concentration difference between water quality parameters is several orders of magnitude. The concentrations of parameters such as Cd, As and Pb are constant. We also try to use the standardized values of physicochemical parameters of groundwater for analysis, but the effect of box diagram can not meet the needs of data analysis. Therefore, in this study, we did not add the box-plot of physicochemical parameters. In order to better compare the dispersion degree of each parameter, we added the coefficient of variation in Table 3.
Point 6: Discussions and conclusions need to be rewritten taking into account previous comments
Response 6: According to the suggestions of all reviewers, the Results and Discussions and Conclusions have been reorganized and improved. Please see the marking in the text for the modification.
Point 7: Recommended works must be added in the bibliography
Response 7: The recommended works by the reviewers have been added to the references.
Author Response File: 
Author Response.docx
Reviewer 2 Report
My observations are:
What is the total area studied?
No where is mentioned about the number of samples and on what basis sampling sites were finalized. Are these samples enough for the entire area
Explain hydrogeology of the area in detail
Samples were collected in 2017 and when these were analysed
In most of the samples anions were measured, but not cations (total hardness was measured- Ca + Mg) please clarify
What methodology and what instrumentation was used for analysis provide details
Author Response
Dear Reviewer,
Thank you for your letter and for the reviewer’s comments concerning our manuscript entitled “Groundwater Quality and Associated Human Health Risk in a Typical Basin of the Eastern Chinese Loess Plateau” (ID: water-1674372). These comments are all valuable and helpful for improving our paper. We have tried our best to revise our manuscript according to the comments. Revised portion are marked up using the “Track Changes” function. The followings are the responses to the reviewer.
Point 1: What is the total area studied?
Response 1: The area of Linfen basin is about 4686 km2. We added the sentence “It covers an area of ∼4686 km2”in Materials and Methods 2.1 (Lines 110-111 ).
Point 2: No where is mentioned about the number of samples and on what basis sampling sites were finalized. Are these samples enough for the entire area？
Response 2: Sorry for this omission. The selection of sampling sites is mainly based on 10 groundwater hydrological monitoring wells set up by Shanxi Provincial Department of Water Resources in the study area. These wells are evenly distributed in each county of the study area, which can represent the groundwater environment of the area. We have added the number of samples in the sentence “Groundwater quality assessment and human health risk assessment based on 10 groundwater hydrological monitoring long-term wells set up by Shanxi Provincial Department of Water Resources in the study area” (Line 158).
Point 3: Explain hydrogeology of the area in detail.
Response 3: Thank you for your suggestion, we full agree with your suggestion. We added detailed geological and hydrogeological conditions of the area (Lines 127-155). A hydrogeological map has also been added (Figure 1). Please see the Methods and materials 2.1 for detailed modifications.
Point 4: Samples were collected in 2017 and when these were analysed.
Response 4: Analysis was carried out immediately(within 24 hours) after sample collection. We emphasized the time of sample analysis in the sentence “All samples were then sealed tightly and sent to the laboratory of Linfen Hydrology and Water Resources Survey Branch for analysis immediately (within 24 hours)”(Line 174).
Point 5: In most of the samples anions were measured, but not cations (total hardness was measured- Ca + Mg) please clarify
Response 5: The purpose of this study was mainly to evaluate the pollution of groundwater in the study area and its safety as a drinking water source. Therefore, the selection and analysis of water quality parameters were carried out according to Chinese national standard for groundwater quality, and cations such as Ca2+, Mg2+,K+ and Na+ were not analyzed. The research team has investigated the spatiotemporal variations of chemical composition of groundwater in the study area, including main cations (Ca2+, Mg2+, Na+, K+) and anions (Cl−, SO42−, HCO3−, CO32−).
(https://doi.org/10.1007/s12145-021-00696-1).
Point 6: What methodology and what instrumentation was used for analysis provide details
Response 6: Thank you for your suggestion, we full agree with your suggestion. Considering the reviewer’s suggestion, we have rewritten the Materials and Methods 2.2 and added detailed methodology (Lines 158-191):
Lines 158-191: Groundwater quality assessment and human health risk assessment based on 10 groundwater hydrological long-term monitoring wells set up by Shanxi Provincial Department of Water Resources in the study area. Groundwater samples were collected in 2017 and were used for the analysis of water quality parameters, including pH, total hardness (TH), total dissolved solids (TDS), sulfate (SO42-), chloride (Cl-), fluoride(F-), cyanide, volatile phenols, chemical oxygen demand (CODMn), nitrate (NO3-N), nitrite (NO2-N), ammonia nitrogen (NH4-N), and PTEs (Fe, Mn, Hg, As, Cd, Cr6+, Pb) for each sample. Sample collection, preservation, transportation and testing were carried out in strict accordance with the Technical Specifications for Environmental Monitoring of Groundwater [56]. Before sampling, wells were pumped for 10 minutes to remove stagnant water. All sampling containers were thoroughly cleaned with groundwater to be sampled. To ensure the stability of the elements, the samples analyzed for TH, Fe, Mn, Cd and Pb were added with HNO3 solution, the samples for the analysis of NH4-N were added with H2SO4 solution, and the samples for cyanide and Cr6+ analysis and for Hg and As analysis were added NaOH and HCl, respectively. All samples were then sealed tightly and sent to the laboratory of Linfen Hydrology and Water Resources Survey Branch for analysis immediately (within 24 hours). pH was measured directly in the field using portable pH meter. TH was analysed by EDTA titration method. TDS was determined by drying and weighing approach. SO42-, Cl−, F−, NH4+, NO3−, and NO2− were tested using ion chromatograph (ICS-600). Fe, Mn, Hg, As, Cd, Cr6+, and Pb were measured using inductively coupled plasma-mass spectrometry (ICP-MS). Groundwater was filtered using 0.45μm filter before their analysis. During the analysis, distilled water and replicates were introduced to ensure the reliability of the results. The replicates had a relative errors within ±5%, indicating acceptable analytical accuracy. IDW interpolation method has been widely used to study the spatial distribution of groundwater quality parameters. IDW uses the deterministic model method to calculate the unknown value according to the nearby points rather than the far off ones. This interpolation method fits well for the real world parameters [37-39]. IDW interpolation results were verified by overlapping field survey data and laboratory analysis results. The pixel values of IDW interpolation map match well with those of field verification data.
Author Response File: Author Response.docx
Reviewer 3 Report
The paper is well structured and organized and presents an outstanding interest work to an international audience. The authors address a very interesting topic regarding the evaluation of the quality and human health risks of groundwater in the Linfen Basin, determining a large set of physical and chemical parameters, and using well-established techniques such as WQI and HHRA. The manuscript is well-written but requires major revisions. I suggest to the author take into account the following suggestions:
- Consider replacing the term Heavy metal in the whole manuscript with the modern term Potentially toxic elements and using the abbreviation PTEs. I invite you to read the interesting manuscript of Pourret et al. 2019 entitled Its Time to Replace the Term Heavy Metals with Potentially Toxic Elements When Reporting Environmental Research which they explain in detail the reasons why this term should be modernized.You should introduce your study in a global context; so, please introduce PTEs, mentioning that is a topic of increasing interest to the scientific community (e.g., study the following paper:doi.org/10.1007/s11356-021-15533-7)
- Use abbreviation for nitrate in the whole manuscript (i.e., NO3-)
- However, for rural areas, it was mainly caused by farmers always applying fertilizers during the period between the rainy and dry season, which will lead to the increase of nitrate in groundwater.. Mention that according to the modern literature fertilizers could increase PTEs concentrations under the appropriate favoring geochemical conditions (e.g, 10.1007/s10661-019-7430-3, 10.1016/j.apgeochem.2020.104697, 10.1002/ieam.4198 )
- You should analyse in detail the geological formations of the study area.
- Please describe the laboratory preparations of your analysis and mention the analytical technique that you measured each chemical element. Do you filter the samples before the analysis? If not, why do you use the dissolved form of the major ions?
- Please mention the analytical method you used for the determination of each parameter.
- Do you determine only Cr(VI) without determining Cr? If yes, provide this information and explain why you choose Cr(VI) instead of Cr. I would like to learn the Cr(VI)/Cr percentage.
- I noticed that the highest Cr6+ concentrations are where the highest NO3 concentrations are. Please discuss this fact mentioning the potential impact/role of agricultural activities in groundwater quality (study 10.1007/s10661-019-7430-3, 10.1016/j.apgeochem.2020.104697)
- How do you define the weights in groundwater quality assessment? Why do you exclude Cr6+ from this procedure? I would expect the Cr6+ to be at the highest class (weight). Please explain in the manuscript.
- The enrichment of Fe, Mn and Pb in groundwater may mainly from coal deposits and pyrite in the study area These concentrations of Fe are high and I strongly believe that this point needs an explanation. Coal deposits are not enough to explain these concentrations. I am concerned that geochemical conditions play a key role, but you need to strengthen this argument.
- Please mention the main disadvantage of the technique you used for interpolation (i.e., bull's eye effect) and comment in the manuscript why you made the best choice between the available methods (e.g., geostatistical methods or other deterministic) and why its main disadvantage will not affect your research.
- Please re-organise your conclusions to answer the hypothesis of your last paragraph of the introduction section.
Author Response
Dear Reviewer,
Thank you for your letter and for the reviewer’s comments concerning our manuscript entitled “Groundwater Quality and Associated Human Health Risk in a Typical Basin of the Eastern Chinese Loess Plateau” (ID: water-1674372). These comments are all valuable and helpful for improving our paper. We have tried our best to revise our manuscript according to the comments. Revised portion are marked up using the “Track Changes” function. The followings are the responses to the reviewer.
Point 1: Consider replacing the term Heavy metal in the whole manuscript with the modern term Potentially toxic elements and using the abbreviation PTEs. I invite you to read the interesting manuscript of Pourret et al. 2019 entitled Its Time to Replace the Term Heavy Metals with Potentially Toxic Elements When Reporting Environmental Research which they explain in detail the reasons why this term should be modernized.You should introduce your study in a global context; so, please introduce PTEs, mentioning that is a topic of increasing interest to the scientific community (e.g., study the following paper:doi.org/10.1007/s11356-021-15533-7)
Response 1: Thank you very much for your valuable advice. After studying the recommended works, we have replaced the heavy metals in this paper with potentially toxic elements (PTEs). The PTEs were introduced in the Introduction as well as Results and discussion 3.1 as follows:
Lines 42-45: Potentially toxic elements (PTEs) in groundwater can cumulate in the human body throughout almost the whole life-span of humans and cause many diseases, which has been a matter of great concern in environmental science and pollution research [18-21].
Lines 330-333: PTEs content in groundwater are usually low. However, even in very low concentrations, they can create biological toxicity and pose serious threats to aquatic ecosystems and human health [20,21,41].
The recommended works by the reviewers have been added to the references.
Point 2: Use abbreviation for nitrate in the whole manuscript (i.e., NO3-)
Response 2: Thank you for your suggestion. We have replaced nitrate with NO3- in the whole manuscript.
Point 3: However, for rural areas, it was mainly caused by farmers always applying fertilizers during the period between the rainy and dry season, which will lead to the increase of nitrate in groundwater. Mention that according to the modern literature fertilizers could increase PTEs concentrations under the appropriate favoring geochemical conditions (e.g, 10.1007/s10661-019-7430-3, 10.1016/j.apgeochem.2020.104697, 10.1002/ieam.4198 )
Response 3: Thank you for your suggestion, we full agree with your suggestion. We have revised this sentence as “Farmers always applying fertilizers during the period between the rainy and dry season, which will lead to the mobilization of NO3- and PTEs from cultivated soils to groundwater under favoring geochemical conditions in dry season. Therefore, the non-carcinogenic risk in dry season is higher than that in rainy season [1,45-48]”(Lines 79-83).
The recommended works by the reviewers have been added to the references.
Point 4: You should analyse in detail the geological formations of the study area.
Response 4: Thank you very much for your valuable advice. We added detailed geological and hydrogeological conditions of the area (Lines 127-155). A hydrogeological map has also been added (Figure 1). Please see the Methods and materials 2.1 for detailed modifications.
Point 5: Please describe the laboratory preparations of your analysis and mention the analytical technique that you measured each chemical element. Do you filter the samples before the analysis? If not, why do you use the dissolved form of the major ions?
Response 5: Groundwater was filtered using 0.45μm filter before their analysis. We added detailed analytical technique for each chemical element in Materials and Methods 2.2 (Lines 176-185).
Lines 176-185: SO42-, Cl−, F−, NH4+, NO3−, and NO2− were tested using ion chromatograph (ICS-600). Fe, Mn, Hg, As, Cd, Cr6+, and Pb were measured using inductively coupled plasma-mass spectrometry (ICP-MS). Groundwater was filtered using 0.45μm filter before their analysis. During the analysis, distilled water and replicates were introduced to ensure the reliability of the results. The replicates had a relative error within ±5%, indicating acceptable analytical accuracy.
Point 6: Please mention the analytical method you used for the determination of each parameter.
Response 6: We added detailed analytical method in Materials and Methods 2.2 (Lines 174-185).
Lines 174-185: pH was measured directly in the field using portable pH meter. TH was analysed by EDTA titration method. TDS was determined by drying and weighing approach. SO42-, Cl−, F−, NH4+, NO3−, and NO2− were tested using ion chromatograph (ICS-600). Fe, Mn, Hg, As, Cd, Cr6+, and Pb were measured using inductively coupled plasma-mass spectrometry (ICP-MS). Groundwater was filtered using 0.45μm filter before their analysis. During the analysis, distilled water and replicates were introduced to ensure the reliability of the results. The replicates had a relative error within ±5%, indicating acceptable analytical accuracy.
Point 7: Do you determine only Cr(VI) without determining Cr? If yes, provide this information and explain why you choose Cr(VI) instead of Cr. I would like to learn the Cr(VI)/Cr percentage.
Response 7: We only analyzed Cr6+. Among chromium compounds, Cr6+ is the most toxic. It can invade human body through digestion, respiratory tract, skin and mucous membrane, and has mutagenicity and carcinogenicity. It is a substance in drinking water that can directly endanger human health. Therefore, in this study, we selected Cr6+ as the water quality parameter based on the evaluation indexes specified in the Chinese national standard for groundwater quality. We plan to expand the study of the Cr(VI)/Cr percentage.
Point 8: I noticed that the highest Cr6+ concentrations are where the highest NO3 concentrations are. Please discuss this fact mentioning the potential impact/role of agricultural activities in groundwater quality (study 10.1007/s10661-019-7430-3, 10.1016/j.apgeochem.2020.104697)
Response 8: Thank you very much for your valuable advice. Considering the reviewer’s suggestion, we have supplemented the corresponding discussion in the article:
Lines 342-347: The similarity in spatial distribution of Cr6+ and NO3- concentrations may be related to the synergistic role of nitrogen (N)-bearing fertilizers to elevated Cr6+ concentration in groundwater. This may be due to the production of H+ and soil acidification during the nitrification process of NH4+ oxidation to NO3−, favoring the increased dissolution of Cr3+ which is subsequently oxidized into Cr6+ by natural and/or anthropogenic factors [46,47].
Lines 474-477: In agricultural activities, the application of N-bearing fertilizers and phosphorous (P)-bearing fertilizers will increase PTEs concentrations such as Cd, Cr, As, Pb in groundwater under the appropriate favoring geochemical conditions [46,47].
Point 9: How do you define the weights in groundwater quality assessment? Why do you exclude Cr6+ from this procedure? I would expect the Cr6+ to be at the highest class (weight). Please explain in the manuscript.
Response 9: We are very sorry for this mistake. Parameters like TH, TDS, SO42-, F-, Fe, Mn, Cd, Cr6+ and Pb were assigned a weight of 5 because of their serious health effects. When the concentration of these parameters is higher than critical concentration limits, it will affect the suitability of groundwater as drinking water and domestic water.
We did not exclude Cr6+ in groundwater quality assessment (Line 200 and Line 350 ). The lack of Cr6+ in Table 4 should be caused by wrong deletion. We have modified Table 4 as follows:
Table 4. Relative weight of physicochemical parameters.
|
Parameters |
Chinese Standards |
Weight(wi) |
Relative Weight (Wi) |
|
pH |
6.5-8.5 |
4 |
0.0588 |
|
TDS |
1000 |
5 |
0.0735 |
|
TH |
450 |
5 |
0.0735 |
|
SO42- |
250 |
5 |
0.0735 |
|
Cl- |
250 |
2 |
0.0294 |
|
F- |
1 |
5 |
0.0735 |
|
Volatile phenols |
0.002 |
2 |
0.0294 |
|
NO3-N |
20 |
4 |
0.0588 |
|
NO2-N |
1 |
4 |
0.0588 |
|
NH4-N |
0.5 |
4 |
0.0588 |
|
Fe |
0.3 |
5 |
0.0735 |
|
Mn |
0.1 |
5 |
0.0735 |
|
Hg |
0.001 |
3 |
0.0441 |
|
Cd |
0.005 |
5 |
0.0735 |
|
Cr6+ |
0.05 |
5 |
0.0735 |
|
Pb |
0.01 |
5 |
0.0735 |
|
|
|
∑wi=68 |
∑Wi=1 |
units for all parameters are in mg/L, except pH (non-dimensional)
Point 10: The enrichment of Fe, Mn and Pb in groundwater may mainly from coal deposits and pyrite in the study area. These concentrations of Fe are high and I strongly believe that this point needs an explanation. Coal deposits are not enough to explain these concentrations. I am concerned that geochemical conditions play a key role, but you need to strengthen this argument.
Response 10: The sentence “the enrichment of Fe, Mn and Pb in groundwater may mainly from coal deposits and pyrite in the study area” was corrected to “Fe and Mn have similar geochemical behavior. Their dissolution and migration to groundwater are affected by reduction conditions, residence time, well depth and salinity[77 ]”(Lines 340-342). At the same time, we also reorganized the relevant parts of Results and discussion 3.2 as follows:
Lines 377-383: Fe and Mn in groundwater comes from coal and metal deposits, especially iron ore. High TDS leads to the increase in ionic strength and the decrease in activity coefficient, which will dissolve more Fe and Mn in groundwater. In addition, the organic matter released from surface pollutants into groundwater can quickly deplete the dissolved oxygen in groundwater, resulting in a reductive hydrochemical environment more conducive to the dissolution of Fe and Mn [77].
Point 11: Please mention the main disadvantage of the technique you used for interpolation (i.e., bull's eye effect) and comment in the manuscript why you made the best choice between the available methods (e.g., geostatistical methods or other deterministic) and why its main disadvantage will not affect your research.
Response 11: We compared different spatial interpolation methods, including IDW, Kriging and natural neighborhood method, and found that the IDW interpolated map is more consistent with the analysis data. The influence of the shortcomings of IDW interpolation method on the results is reduced by optimizing the power parameters and assigning the weight reasonably. We added the introduction of IDW interpolation method in Materials and Methods 2.2 (Lines 185-191).
Lines 185-191: IDW interpolation method has been widely used to study the spatial distribution of groundwater quality parameters. IDW uses the deterministic model method to calculate the unknown value according to the nearby points rather than the far off ones. This interpolation method fits well for the real world parameters [30-32]. IDW interpolation results were verified by overlapping field survey data and laboratory analysis results. The pixel values of IDW interpolation map match well with those of field verification data.
Point 12: Please re-organise your conclusions to answer the hypothesis of your last paragraph of the introduction section.
Response 12: We have made appropriate modifications to conclusion:
Lines 495-528: In this study, groundwater samples from Linfen Basin were collected and analyzed for physicochemical parameters. The water quality index was used to evaluate the groundwater quality, while the health risk was assessed for adults and children considering different exposure pathways. The main conclusions of the study are as follows:
The groundwater in the study area is weakly alkaline, with TH and TDS ranging within 167- 869 and 280-1312 mg/L. Compared with the Chinese national standards, 30%, 10%, 20%, 20%, 10%, 10% and 100% of the total samples exceeded the standard limits of drinking water in terms of TH, TDS, SO42-, F-, Fe, Mn and Pb. Higher TH, TDS, SO42-, Fe and Mn are mainly distributed in the southeastern part of the study area, while high concentration of F- is observed in the central area of the study area.
Most of the groundwater has good water quality and can be used as drinking water. Eight samples belong to excellent water, one sample is categorized good water and one sample is classified as poor water. Pb, TH, F-, SO42- and TDS are the most significant parameters affecting groundwater quality. The poor quality of groundwater near Yicheng might be due to the shallow buried depth of groundwater and the good permeability of aquifer.
Contaminated groundwater in the study area can pose human health risks to residents through multiple exposure pathways, including drinking water intake and dermal contact. The total non-carcinogenic health risks for males, females and children range from 0.302 to 0.902, 0.354 -1.051 and 0.719-2.100, respectively. Males do not have associated non-carcinogenic health risks while females and children face higher non-carcinogenic risk than males. The ranges of the total carcinogenic health risks for males, females and children are 7.371×10-5-1.605×10-4, 8.541×10-5-1.837×10-4 and 4.386×10-5-9.121×10-5, respectively. The carcinogenic risk exceeds acceptable limit recommended by the Ministry of Ecology and Environment of the P. R. China for both adults and children. The great risky area (HItotal > 1 and CRtotal>1×10-6) of adults and children all occur in the central of the study area.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
Remarks from reviewers have been correctly addressed, and the paper is now more focuse on his core topic
In my opinion it is now acceptable.
Best regards
Reviewer 2 Report
Revised manuscript is much improved
Reviewer 3 Report
The manuscript has been improved based on the comments, and I suggest it for publication!
