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  • July 20, 2022

    Talking About Parts Per Quadrillion: Public Health Messaging and PFAS

    With a new advisory regarding a PFAS compound from the Environmental Protection Agency, Wisconsin is finalizing an enforceable drinking water administrative rule – and it can be the task of environmental law attorneys to communicate these changes with the public. Bill Nelson discusses best practices for public health messaging regarding PFAS.

    William John Nelson

    “I don’t have the trust with (Wisconsin) DHS.” – Wisconsin Natural Resources Board member Terry Hilgenberg, Feb. 23, 2022.1

    On Feb. 23, 2022, the Wisconsin Department of Natural Resources (DNR) regulatory policy-setting body, the Natural Resources Board (NRB), met to discuss three proposed final rules to regulate per- and polyfluorinated substances (PFAS) in drinking water, wastewater (through surface water criteria), and groundwater.

    In that meeting, the NRB unilaterally increased the proposed final drinking water standard from the Wisconsin Department of Health Services (DHS) recommended value of 20 parts per trillion (ppt) to 70 ppt for PFOA and PFOS, killed the proposed groundwater regulation, and passed the proposed wastewater regulation.2

    During the meeting, after bemoaning COVID-19-related mask regulations in effect at the time in Dane County, NRB member Terry Hilgenberg proclaimed that one of the reasons he did not trust the recommended values underlying the proposed DNR regulations at 20 ppt was his distrust of Wisconsin DHS officials.

    The statutorily created process for DNR, to the request recommendation of enforcement standards for substances of public health concern from DHS, is established by Wis. Stat. section 160.07.

    If the COVID-19 pandemic has taught us anything as a society – aside from how to participate in virtual meetings – it is that public health officials on the federal, state, and local levels face an increasingly difficult job effectively communicating health exposure risks to the public.

    Environmental practitioners must also become fluent in appropriate messaging regarding PFAS, particularly where thresholds of regulation are being set at never before considered infinitesimal levels.

    The purpose of this article is to highlight the significant recent changes in EPA public health messaging regarding PFAS, and how that may affect the framework for discussing these “forever chemicals” in Wisconsin.

    Bill Nelson headshot Bill Nelson, Marquette 2013, is an associate attorney with Godfrey & Kahn, S.C., environmental strategies team based in Madison. He focuses on PFAS, Brownfields redevelopment, environmental compliance, and other complex land use issues.

    Significance of Health Advisory Levels

    Recent and future EPA actions to address PFAS under multiple regulatory programs are outlined in the October 2021 federal PFAS Strategic Roadmap. The two most studied analytes, PFOA and PFOS, are to be imminently designated (i) in a draft rule as hazardous substances under CERCLA and (ii) in a proposed draft rule setting a maximum contaminant level (MCL) in drinking water (contemplated for fall 2022).

    The PFAS Strategic Roadmap also tasked EPA with issuing updated health advisory levels (HALs) for PFOA and PFOS as well as final HALs for the replacement chemistry for numerous applications of PFOA and PFOS: PFBS and GenX chemicals.

    HALs are references to the greatest amount of a contaminant an adult can ingest daily over the course of a lifetime without experiencing health risks. On June 15, 2022, EPA released the following HALs for the four PFAS:3


    Minimum Reporting Level (ppt)

    Lifetime Health Advisory Level (ppt)



    0.004 (Interim)



    0.02 (Interim)

    GenX Chemicals


    10 (Final)



    2,000 (Final)

    The interim HALs for PFOA and PFOS are below the detection limit, the level that a laboratory can confidently identify a concentration of a substance in a sample. This means that EPA does not recommend drinking any water with any PFOA and PFOS detected in the sample.

    Prior to June 15, EPA’s recommended HAL for PFOA was 70 ppt, a figure recommended by the agency in 2016. While the recently updated HALs are “interim,” the reason they are interim is due to recent human health studies linking PFOA and PFOS exposure to COVID-19 vaccine ineffectiveness.4

    Wisconsin Administrative Rules and ‘Low’ Levels of PFAS in Drinking Water

    The NRB and Wisconsin Legislature allowed DNR and DHS to promulgate drinking water rules regulating PFOA and PFOS to 70 ppt. This value is 17,500 times greater than the 4 parts per quadrillion (ppq) recommended HAL for PFOA set by EPA.

    For five months, Wisconsin DNR and DHS officials had to grapple with the conundrum of regulating PFAS in drinking water at 70 ppt when health officials recommend 20 ppt. Now, DNR, DHS, and environmental practitioners must be able to converse with newly updated federal advisories, including correlating DNR’s developing parts per trillion regulatory standards for drinking water and wastewater and, eventually, groundwater, with the federal HALs that are orders of magnitude less, in the parts per quadrillion.

    Best Practices for Communicating PFAS Sampling Results

    Having worn the hat of a PFAS regulator and now representing the regulated community, I offer a few suggested best practices regarding communicating the risks associated with PFAS in the environment, to avoid public health messaging mistakes:

    • For PFAS sampling results, don’t describe PFAS as “low levels.” Recognize that the EPA HALs essentially mean that any detectable level of PFOA and PFOS represents an unacceptable level of PFAS in drinking water.

    • For PFAS sampling results, specify the test method utilized and suite of analytes included in the testing.

    • Where possible, compare PFAS results to both enforceable values and recommended values. Know that the DNR will consider the recommended values as points of reference, so regulated parties should do the same. Avoid limiting the analysis interpreting the results to only PFOA and PFOS.

    • In the context of a remedial action site where PFAS is present in the groundwater, utilize Wis. Admin. Code § NR 722.09(2)(b)2 to calculate a site-specific value.

    • Consider advising clients to prepare a “total PFAS” aggregate concentration for reference.

    • Until there is an accepted regulation of PFAS as a group – such as PAHs, PCBs, and other contaminants – discussion of these chemicals will be complicated. Be prepared to discuss these concepts creatively.

    • Adopt a humility-based approach to the underlying science. When advising clients about the developments in PFAS exposure concerns, choose an approach that accepts analytical curiosity over narrow-minded certainty, because this area will continue to evolve until scientific consensus is achieved.

    The regulation of PFAS in Wisconsin is just getting started – the NRB’s February meeting did not end the process. With enforceable standards on track for wastewater permits and drinking water supplies for PFOA and PFOS, DNR has additional rulemaking for 11 other analytes to be completed by 2024.

    EPA’s PFAS Strategic Roadmap will drive national conversations around PFAS, but Wisconsin residents will soon know better where PFAS is present, thanks to DNR-required municipal sampling for PFOA and PFOS beginning this fall and federal UCMR 5 testing of 29 PFAS analytes for all public water systems beginning in January 2023.5

    While certain parties may never accept the premise of regulating any contaminant at levels in the parts per quadrillion, most parties will be interested to learn how to meet currently effective and developing requirements in addressing PFAS in the environment.

    Build trust with your clients and with regulatory agencies through implementing these best practices for communicating PFAS sampling results and exposure risks.

    This article was originally published on the State Bar of Wisconsin’s Environmental Law Section Blog. Visit the State Bar sections or the Environmental Law Section webpages to learn more about the benefits of section membership.


    1 Hour 4, Minute 35 of Feb. 23, 2022, NRB Meeting, available on the Wisconsin DNR website.

    2 For discussion of these PFAS rules, see Vanessa Wishart’s April 27, 2022, article “An Update on PFAS Regulation in Wisconsin” on the State Bar of Wisconsin Environmental Law Section Blog.

    3 Questions and Answers: Drinking Water Health Advisories for PFOA, PFOS, GenX Chemicals and PFBS,

    4 Id., Question 13.

    5 For more, see “PFAS: EPA to require all public water systems to sample 29 analytes beginning in 2023,” March 14, 2022, Insights & Events, Godfrey & Kahn, S.C.

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    Environmental Law Blog is published by the State Bar of Wisconsin. To contribute to this blog, contact Gabe Johnson-Karp and review Author Submission Guidelines. Learn more about the Environmental Law Section or become a member.

    Disclaimer: Views presented in blog posts are those of the blog post authors, not necessarily those of the Section or the State Bar of Wisconsin. Due to the rapidly changing nature of law and our reliance on information provided by outside sources, the State Bar of Wisconsin makes no warranty or guarantee concerning the accuracy or completeness of this content.

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