PONE-D-23-08184

A comprehensive survey and analysis of international drinking water regulations for inorganic chemicals with comparisons to the World Health Organization’s drinking-water guidelines

PLOS ONE

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***We request an exception to this policy concerning the citation of unpublished manuscripts in this case. The only reason why we are making reference to this unavailable document is that the WHO has used it as the basis for its drinking water guideline. The table in which this reference occurs has been constructed as a comprehensive reference list to enable readers to identify all studies on which the WHO guidelines are based; this information has never been collated in published documents before. It was the WHO, not ourselves, that chose to cite an unpublished, unavailable document. In this footnote, we wish to highlight the fact that the guideline is based on an unpublished document, and that we were denied access to this document when we requested it from the agency that created it. For the sake of completeness for the table, it is extremely important that we be able to list the complete reference information as the WHO provided it in their citations documenting their guideline.

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***We created our map ourselves using the ggmap package in R. As requested in the reference document for the ggmap package (https://cran.r-project.org/web/packages/ggmap/citation.html), we have cited the authors of the ggmap package (Kahle and Wickham, 2013) since they provided the source code for the base maps on a CC by 4.0 basis. The ggmap source code was based on the public domain Natural Earth project. We have added a citation to Kahle and Wickham, 2013 [30] to our figure caption. The map was not made with any copyrighted materials and it is suitable for CC by 4.0 licensing as is.

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***Done.

Reviewer #1: The manuscript entitles “A comprehensive survey and analysis of international drinking water regulations for inorganic chemicals with comparisons to the World Health Organization’s drinking- water guidelines” needs major revision before publishing in the journal:

- In the page 5, line 141, “μg/L”, and “mg/L” were mentioned as searched terms, are these two terms suitable for finding papers or other publications???!!!

***For many countries, finding copies of the national drinking water regulations was extremely difficult. If an initial search did not turn up a required document, we tried many, many alternative search strategies. One of the most successful strategies was to search “μg/L” or “mg/L” in combination with “drinking water” and the name of the country. This was often a successful search method because many drinking water regulations refer to these units, so the units are contained as text within the document. Since these are international units, they are constant, regardless of the language of the document, so they do not need to be translated into local languages for searching. Note that this search task was used to find national drinking water regulations, which are specific and unique documents. Such a search task is quite different from the open-ended task of identifying research papers on a specific topic.

No changes made.

- The type of study was mentioned as research article but the present study is review article. So correct the type of study after that mention the search strategy.

***Although this project required database searching for published documents, it represents original research, rather than a review article. A review article collates and compares data collected by other scientists; the data have all been previously analyzed before they are reconsidered or summarized in the review. In contrast, the documents that we searched for to create our database were primary regulatory documents. We created a database of datapoints collated from these primary regulatory documents; the datapoints were levels set by regulators and not the results of any prior scientific studies. After we collated the database of regulatory datapoints, we performed original and novel analyses of these datapoints. These analyses revealed new patterns across this entirely novel dataset, patterns which will likely be of interest and use to regulators and drinking water scientists.

No changes made.

- Mention the full name of elements for the first time after that use abbreviations.

***Done

- The aims of the study were not mentioned and the content is not well classified.

***Thank you for pointing out this weakness. We have re-written the final paragraph of our introduction to clarify these points.

- Use the methods of the following studies to improve the manuscript:

- Emerging contaminants migration from pipes used in drinking water distribution systems: a review of the scientific literature. Environmental Science and Pollution Research (2022), pp.1-27.

- Evaluation of occurrence of organic, inorganic, and microbial contaminants in bottled drinking water and comparison with international guidelines: a worldwide review. Environmental Science and Pollution Research (2022), pp.1-15.

***While these are quite interesting and important articles, both of them are scientific reviews. They analyze the results of other scientific studies that were previously published. Our manuscript, in contrast, is not a review, but rather a novel scientific study. Our manuscript analyzes datapoints collated from primary regulatory documents. Although the collation of the regulatory documents involved database and internet searching, the inclusion of a systematic search process in our methods does not make the manuscript a review paper since we did not analyze any previously published research articles. Since the review articles mentioned above were of an entirely different genre, their methods are not relevant for the original research project that we completed.

No changes made.