Drinking Bottled and Tap Water for Healthier Living in Volcanic Areas: Are All Waters the Same?
Round 1
Reviewer 1 Report
This article reports a study on potential fluoride issues occurring locally in Portugal. The article prepared well in general with careful sample analysis and discussion. However, some minor problems/concerns have been found. Please see comments shown below.
Abstract: The abstract needs to be improved. You do not need to indicate what is background or others. Please make them coherent as an integral paragraph.
Lines 37 to 38, “…however, the long-term consumption of water containing 1 mg of fluoride per liter leads to dental fluorosis…”: This is confusing. Is 1mg/L fluoride good or not? You just mentioned it is beneficial. In addition, the amount of fluoride that is taken by a person also depends on how much water he/she drinks, not just the fluoride concentration.
Line 53, “265 L per capita”: Is this value for per year? Please make the expression accurate.
Line 60: Again, indicate the time scale of these numbers. What is still water?
Lines 70 to 71, “… especially in volcanic areas with waters naturally enriched with fluoride such as the Azores”: The logic needs to be improved. People in volcanic areas do not necessarily consume bottled water produced in volcanic areas. The logic of the title of this article should be improved too.
Lines 72 to 74: Show quantitative information of how high the fluoride is.
Line 135: How does 0.06 mg/day/kg correspond to 1 mg/L? A child with a weight of 10 kg is quite low.
Lines 149 to 151: Improve the writing.
Table 1: Improve Table 1. It is confusing that there are two rows showing fluoride concentrations. What do a, b, c, and d mean?
Line 179: Where can I find "different letters"?
Figure 1: The x-axis should have a label with a unit showing what it means. If applicable, please show the error bars representing the standard deviations of multiple measurements.
Figure 2: The y-axis should have a label with a unit showing what it means. If applicable, please show the error bars representing the standard deviations of multiple measurements.
Line 229: The sentence is confusing, needing an improvement.
Line 235: What method is used to control fluoride concentration?
Author Response
This article reports a study on potential fluoride issues occurring locally in Portugal. The article prepared well in general with careful sample analysis and discussion. However, some minor problems/concerns have been found. Please see comments shown below.
Abstract: The abstract needs to be improved. You do not need to indicate what is background or others. Please make them coherent as an integral paragraph.
The authors have eliminated the indication of background and others and, built one integral paragraph (see abstract).
Lines 37 to 38, “…however, the long-term consumption of water containing 1 mg of fluoride per liter leads to dental fluorosis…”: This is confusing. Is 1mg/L fluoride good or not? You just mentioned it is beneficial. In addition, the amount of fluoride that is taken by a person also depends on how much water he/she drinks, not just the fluoride concentration.
The authors took the reviewer remark in consideration and rephrased the paragraph (see lines 37-39).
Line 53, “265 L per capita”: Is this value for per year? Please make the expression accurate.
The authors have corrected the expression to per capita/ year (see line 53).
Line 60: Again, indicate the time scale of these numbers. What is still water?
The authors have added a time scale to the numbers (see lines 57-61). For still water we considered to be all the bottled water that are not-gasified; this information was also added to the manuscript (see line 60).
Lines 70 to 71, “… especially in volcanic areas with waters naturally enriched with fluoride such as the Azores”: The logic needs to be improved. People in volcanic areas do not necessarily consume bottled water produced in volcanic areas. The logic of the title of this article should be improved too.
The authors took in consideration the reviewer remark and rephrased the sentence. As for the logic, we believe it is also improved as in the Azorean context, due to volcanic activity and a general concern related to the quality of tap water, most of the inhabitants tend to believe and prefer bottled water (see lines 71-74).
Lines 72 to 74: Show quantitative information of how high the fluoride is.
The authors have added this information to the manuscript (see lines 75-79).
Line 135: How does 0.06 mg/day/kg correspond to 1 mg/L? A child with a weight of 10 kg is quite low.
The adequate intake for fluoride from all sources was set at 0.06 mg/day/kg body weight; The higher the weight, higher is the possibility of ingesting fluoride without causing harm.
For instance, in a case of a tap water with 1.5mgF/L
The Daily intake (DI) = C x V will be of 0.375mgF for an ingested volume of 0.250L water.
Considering a child with 10Kg we must divide 0.375 per 10kg and the DI will be of 0.0375 and, for and adult with 70 kg we must divide 0.375 per 70 kg and the DI will be of 0.005mgF.
This means that for a child the risk of exceeding an adequate fluoride intake is very high as a consumption of 0.500L of water in any source with this concentration will lead to an excessive consumption. While in an adult, the consumption of this water in any source would have to be higher than 3L.
We have considered a child with 10kg as this corresponds to 8-9 months old; at this time, a child starts to have several elements included in their diet that can be prepared with water such as beverages, soups, and formulas.
Lines 149 to 151: Improve the writing.
The authors thank the reviewer’s remark and have improved the writing to the sentence (see lines 154-159).
Table 1: Improve Table 1. It is confusing that there are two rows showing fluoride concentrations. What do a, b, c, and d mean?
As for this table, the two rows showing fluoride concentrations correspond to: 1) the mean fluoride concentration on the counties (Povoação, Ribeira Grande and Ponta Delgada) and the specific target villages within these counties (Furnas, Ribeira Quente, Porto Formoso and Sete Cidades).
The letters a, b, c and d represent significant differences between the sites (as indicated in the table caption). In the case of this study, the fluoride concentration, on the tap waters from the 4 considered villages, was significantly different comparing all villages.
Line 179: Where can I find "different letters"?
The different letters are found in the table 1. The fluoride concentration on the countries and in the villages in followed by a letter that indicated if concentrations are significantly different (different letters) or if they are similar (same letters). The table captation has this information also (Different letters within each line represent significant differences between sites (p< 0.05))
Figure 1: The x-axis should have a label with a unit showing what it means. If applicable, please show the error bars representing the standard deviations of multiple measurements.
The authors added to the figure the label of the x-axis with the correspondent units; as it is the daily intake that is represented, there is no error bars (see figure 1).
Figure 2: The y-axis should have a label with a unit showing what it means. If applicable, please show the error bars representing the standard deviations of multiple measurements.
The authors thank the reviewer’s remark but considering that in this figure there are represented two different measurements (IT and NHQ) with different label units, it is not possible to include one label on the y-axis. Still, authors added in the captation that IT is measured in mg/kg/day (see figure 2).
Line 229: The sentence is confusing, needing an improvement.
The authors have improved the sentence according to reviewer remark (see lines 236-239).
Line 235: What method is used to control fluoride concentration?
The most common methods are reverse osmosis and chemical coagulation. Each county and the company responsible for water treatment define what method to use.
Author Response File: 
Author Response.docx
Reviewer 2 Report
The manuscript “water-1842947” aimed to assess fluoride concentration in tap and bottled water consumed in São Miguel Island assessing the fluoride daily intake, risk exposure and, discussing the possible health effects in adults and children
The paper needs of a strong revision before publication in order to increase its impact on scientific community.
Abstract:
Please delete the section: background, methods, results and discussion. Point division is not preferred for abstract.
Introduction:
The introduction section must be improved especially with regard to geological framework, hydrogeochemical processes and enrichment of fluoride including fluoride source and fate, fluoride concentration in rocks of interest etc.
I suggest the papers reported below to take inspiration:
Mwiathi, N. F., Gao, X., Li, C., & Rashid, A. (2022). The occurrence of geogenic fluoride in shallow aquifers of Kenya Rift Valley and its implications in groundwater management. Ecotoxicology and Environmental Safety, 229, 113046.
· Fuoco, I., Apollaro, C., Criscuoli, A., De Rosa, R., Velizarov, S., & Figoli, A. (2021). Fluoride Polluted Groundwaters in Calabria Region (Southern Italy): Natural Source and Remediation. Water, 13(12), 1626.
· Olaka, L. A., Wilke, F. D., Olago, D. O., Odada, E. O., Mulch, A., & Musolff, A. (2016). Groundwater fluoride enrichment in an active rift setting: Central Kenya Rift case study. Science of the Total Environment, 545, 641-653.
· Fuoco, I., Marini, L., De Rosa, R., Figoli, A., Gabriele, B., & Apollaro, C. (2022). Use of reaction path modelling to investigate the evolution of water chemistry in shallow to deep crystalline aquifers with a special focus on fluoride. Science of The Total Environment, 830, 154566.
Jha, S. K., Mishra, V. K., Sharma, D. K., & Damodaran, T. (2011). Fluoride in the environment and its metabolism in humans. Reviews of Environmental Contamination and Toxicology Volume 211, 121-142.
Hu, B., Song, X., Lu, Y., Liang, S., & Liu, G. (2022). Fluoride enrichment mechanisms and related health risks of groundwater in the transition zone of geomorphic units, northern China. Environmental Research, 113588.
Material and Methods
Specify the sampling methods. For instance filtering process and measurement of labile parameters. Describe the method used to analyze the other major elements (Cl,NO3 , Na, Ca, Mg) reported in supplementary materials. How these data were validate? Charge balance?
Moreover, report in the table all performed analysis or all statistic parameters for each group of waters ( at least min, max, sd, mean, median) for all analyzed elements.
Add also a geological/hydrogeological map of the area, plotting the sampling points. Probably, there is not a correspondence among sampling point and natural water outlet. For these reasons a discussion about the hydrogeological framework and occurring hydrogeochemical processes will allow to the readers to better understand the environmental issue.
FIGURE 1 and FIGURE 2.
Add unit in the graphs
RESULTS AND DISCUSSION
Improve the sections inserting a comparative discussion among the geochemical processes responsible of tap and bottled waters mineralization considering the hydrogeological framework.
REFERENCES
1. Add the following papers in the references list, remembering to re-number the citations throughout the text
Mwiathi, N. F., Gao, X., Li, C., & Rashid, A. (2022). The occurrence of geogenic fluoride in shallow aquifers of Kenya Rift Valley and its implications in groundwater management. Ecotoxicology and Environmental Safety, 229, 113046.
· Fuoco, I., Apollaro, C., Criscuoli, A., De Rosa, R., Velizarov, S., & Figoli, A. (2021). Fluoride Polluted Groundwaters in Calabria Region (Southern Italy): Natural Source and Remediation. Water, 13(12), 1626.
· Olaka, L. A., Wilke, F. D., Olago, D. O., Odada, E. O., Mulch, A., & Musolff, A. (2016). Groundwater fluoride enrichment in an active rift setting: Central Kenya Rift case study. Science of the Total Environment, 545, 641-653.
·Fuoco, I., Marini, L., De Rosa, R., Figoli, A., Gabriele, B., & Apollaro, C. (2022). Use of reaction path modelling to investigate the evolution of water chemistry in shallow to deep crystalline aquifers with a special focus on fluoride. Science of The Total Environment, 830, 154566.
Jha, S. K., Mishra, V. K., Sharma, D. K., & Damodaran, T. (2011). Fluoride in the environment and its metabolism in humans. Reviews of Environmental Contamination and Toxicology Volume 211, 121-142.
· Hu, B., Song, X., Lu, Y., Liang, S., & Liu, G. (2022). Fluoride enrichment mechanisms and related health risks of groundwater in the transition zone of geomorphic units, northern China. Environmental Research, 113588.
Author Response
The manuscript “water-1842947” aimed to assess fluoride concentration in tap and bottled water consumed in São Miguel Island assessing the fluoride daily intake, risk exposure and, discussing the possible health effects in adults and children
The paper needs of a strong revision before publication in order to increase its impact on scientific community.
Abstract:
Please delete the section: background, methods, results and discussion. Point division is not preferred for abstract.
The authors have deleted the section background, methods, results and discussion and built one integral paragraph (see abstract).
Introduction:
The introduction section must be improved especially with regard to geological framework, hydrogeochemical processes and enrichment of fluoride including fluoride source and fate, fluoride concentration in rocks of interest etc.
I suggest the papers reported below to take inspiration:
Mwiathi, N. F., Gao, X., Li, C., & Rashid, A. (2022). The occurrence of geogenic fluoride in shallow aquifers of Kenya Rift Valley and its implications in groundwater management. Ecotoxicology and Environmental Safety, 229, 113046.
Fuoco, I., Apollaro, C., Criscuoli, A., De Rosa, R., Velizarov, S., & Figoli, A. (2021). Fluoride Polluted Groundwaters in Calabria Region (Southern Italy): Natural Source and Remediation. Water, 13(12), 1626.
Olaka, L. A., Wilke, F. D., Olago, D. O., Odada, E. O., Mulch, A., & Musolff, A. (2016). Groundwater fluoride enrichment in an active rift setting: Central Kenya Rift case study. Science of the Total Environment, 545, 641-653.
Fuoco, I., Marini, L., De Rosa, R., Figoli, A., Gabriele, B., & Apollaro, C. (2022). Use of reaction path modelling to investigate the evolution of water chemistry in shallow to deep crystalline aquifers with a special focus on fluoride. Science of The Total Environment, 830, 154566.
Jha, S. K., Mishra, V. K., Sharma, D. K., & Damodaran, T. (2011). Fluoride in the environment and its metabolism in humans. Reviews of Environmental Contamination and Toxicology Volume 211, 121-142.
Hu, B., Song, X., Lu, Y., Liang, S., & Liu, G. (2022). Fluoride enrichment mechanisms and related health risks of groundwater in the transition zone of geomorphic units, northern China. Environmental Research, 113588.
The authors understand the reviewer’s point of view and have added more information regarding the geological framework (see lines 71-80). Still, this study is mainly focused on the fluoride concentration on bottled water and therefore we believe that adding more information regarding fluoride source and fate and fluoride concentration in rocks may diverge the MS focus.
Material and Methods
Specify the sampling methods. For instance, filtering process and measurement of labile parameters. Describe the method used to analyze the other major elements (Cl, NO3, Na, Ca, Mg) reported in supplementary materials. How these data were validate? Charge balance?
The authors did not do any filtering process. The only parameter measured in our laboratory was fluoride by ion-selection electrode. The remaining elements presented in supplementary material were acquired on the city councils records available online.
Moreover, report in the table all performed analysis or all statistic parameters for each group of waters (at least min, max, sd, mean, median) for all analyzed elements.
The indication of mean and SE is presented in all the tables of the MS. The results presented in table 1 and 2 are a combined value of three replicates for sample, the authors don’t see the need to add more information but if the reviewer still considers important to add min, max, mean and SD, authors will add this information in supplementary material.
Add also a geological/hydrogeological map of the area, plotting the sampling points. Probably, there is not a correspondence among sampling point and natural water outlet. For these reasons a discussion about the hydrogeological framework and occurring hydrogeochemical processes will allow to the readers to better understand the environmental issue.
The only sampling points correspond to the tap water collected in the households; we do not have authorization from the owners to display this information, still, we can build a figure showing the villages and the counties if the reviewer considers necessary.
The authors toke the reviewer remark in consideration and added in the discussion information regarding the hydrogeological framework (see lines 240-249).
FIGURE 1 and FIGURE 2.
Add unit in the graphs
The authors have added units to the figure 1. But for figure 2, considering that in this figure there are represented two different measurements (IT and NHQ) with different label units, it is not possible to include one label on the y-axis. Still, authors added in the captation that IT is measured in mg/kg/day (see figure 2).
RESULTS AND DISCUSSION
Improve the sections inserting a comparative discussion among the geochemical processes responsible of tap and bottled waters mineralization considering the hydrogeological framework.
Information regarding the hydrogeological framework was added in the discussion (see lines XX).
REFERENCES
Add the following papers in the references list, remembering to re-number the citations throughout the text
Mwiathi, N. F., Gao, X., Li, C., & Rashid, A. (2022). The occurrence of geogenic fluoride in shallow aquifers of Kenya Rift Valley and its implications in groundwater management. Ecotoxicology and Environmental Safety, 229, 113046.
Fuoco, I., Apollaro, C., Criscuoli, A., De Rosa, R., Velizarov, S., & Figoli, A. (2021). Fluoride Polluted Groundwaters in Calabria Region (Southern Italy): Natural Source and Remediation. Water, 13(12), 1626.
Olaka, L. A., Wilke, F. D., Olago, D. O., Odada, E. O., Mulch, A., & Musolff, A. (2016). Groundwater fluoride enrichment in an active rift setting: Central Kenya Rift case study. Science of the Total Environment, 545, 641-653.
Fuoco, I., Marini, L., De Rosa, R., Figoli, A., Gabriele, B., & Apollaro, C. (2022). Use of reaction path modelling to investigate the evolution of water chemistry in shallow to deep crystalline aquifers with a special focus on fluoride. Science of The Total Environment, 830, 154566.
Jha, S. K., Mishra, V. K., Sharma, D. K., & Damodaran, T. (2011). Fluoride in the environment and its metabolism in humans. Reviews of Environmental Contamination and Toxicology Volume 211, 121-142.
Hu, B., Song, X., Lu, Y., Liang, S., & Liu, G. (2022). Fluoride enrichment mechanisms and related health risks of groundwater in the transition zone of geomorphic units, northern China. Environmental Research, 113588.
The authors took inspiration in most of the presented references, these are present along the MS and in the reference section.
Author Response File: Author Response.docx
Round 2
Reviewer 2 Report
I think that provided more information about source of contamintant give greater strength to the research. The water-rock interaction process governs the fluorine concentrations in the studied waters. More information needs to be added.
The table must be improved as required in the first revision as well as the figure, if possible.
Author Response
I think that provided more information about source of contamintant give greater strength to the research. The water-rock interaction process governs the fluorine concentrations in the studied waters. More information needs to be added.
The authors toke the reviewer remark in to consideration and added more information in the introduction of the MS (see lines 75-85).
The table must be improved as required in the first revision as well as the figure, if possible.
The authors have improved table 1 and included the reviewer sugestions (see table 1). The authors also built a new figure 2 and added more information on the captation ( see figure 2).
Author Response File: Author Response.docx
