Water & Health Advisory Council submits Public Comment on WHO PFOS/PFOA Guidelines for Drinking Water

November 18, 2022


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The Water & Health Advisory Council recently submitted a public comment on the World Health Organization’s guidelines for drinking water quality. Read the full public comment below.


November 10, 2022 

To the World Health Organization (WHO):

RE: PFOS and PFOA in Drinking-water, Draft background document for development of WHO Guidelines for Drinking-water Quality


Thank you for the opportunity to provide comments on your recently released PFOS/PFOA drinking water guidelines.The Water & Health Advisory Council’s (WHAC’s) mission is to provide clarity and context to drinking water utilities and policymakers, public health professionals, and the public to help navigate complex issues and assure the protection of the U.S. drinking water supply. We advocate a risk-based approach to identifying, addressing and prioritizing the challenges associated with delivering safe drinking water, including emerging contaminants. We encourage decision makers at all levels of government to deal with the greatest health concerns first so that public health benefits will be maximized.


We believe that PFAS chemicals should be managed and regulated consistently in the U.S. and internationally at scientifically-based levels. We commend the World Health Organization (WHO) for tackling this complex issue with a thoughtful and balanced assessment of the available data and arriving at a reasonable and practical conclusion. It reflects the conclusions that most countries have reached on PFAS chemicals. WHO’s guidance is based upon their assessment that the best available science is inconclusive on potential human health risks linked to exposure to these substances in drinking water and other sources.


We agree with WHO’s recommendation of 0.1 ppb each for PFOA and PFOS, however, it would not be appropriate to manage all PFAS chemicals as a single class because of their widely differing toxicology. The proposed total PFAS value of 0.5 ppb is not appropriate as currently described. There is a very wide range of toxicology information available on numerous PFAS chemicals. Some like PFBA have recommended values in the thousands of parts per trillion (PPT). It would be appropriate to identify several groupings of PFAS chemicals with an associated aggregate guideline value. The categorizations and chemicals included in each group could be based on reported Health Values that have been computed in several countries.


The issue of related antibodies reduction for diphtheria and tetanus is significant because it is a very sensitive biological endpoint. An important question is at what point the antibody level significantly increases risk of contracting a particular disease. The Antoniou et al publication Archives of Toxicology 2022 that addresses this issue is cited, but it was not described so public review and comment possibilities were limited. Those authors provided a very detailed review and critique of reported animal and human studies and concluded that:


“The overall level of evidence regarding associations between PFAS serum levels and reduced antibody response remains weak. Absence of an association between an increase in clinical infections and PFAS serum levels and the limited understanding of the importance of antibody levels as an isolated data point further support this conclusion. Animal toxicity studies with PFAS focusing on immunomodulation also provide only limited support for immunomodulation as an important endpoint in PFAS toxicity. While immunomodulation is observed after PFAS administration, generally at blood concentrations several orders of magnitude above those seen in environmentally exposed humans, the relevance of these observation is hampered by the high doses required to influence immune endpoints, the limited number of endpoints assessed, and inconsistent results. The limitations of the current database on associations of human PFAS exposures outlined here indicate that more evidence is required to select immunomodulation as a critical endpoint for human PFAS risk assessment.”


According to U.S. Centers for Disease Control and Prevention (CDC) reports, there is no indication of infectious disease incidences in the USA for diphtheria and tetanus associated with PFOA or PFOS blood levels, even during the period of much higher PFOS and PFOA concentrations and prevalence in the U.S. environment and blood. Cases have declined significantly even during the increased introduction of PFOA and PFOS in commerce (https://cdc.gov/nchs/hus/contents2019.htm#table-010) due to the introduction of and widespread vaccinations in the population.


We applaud the WHO for utilizing the available science to come to a reasonable and practical analysis and international guidelines. And we appreciate your consideration of our comments.



Water & Health Advisory Council

Download the public comment here.

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