Toxicologist talks PFAS health advisories and environmental whack-a-mole


Jamie Dewitt: I’m Dr. Jamie Dewitt. I’m a professor in the department of pharmacology and toxicology of the Brody School of Medicine at East Carolina University in Greenville, North Carolina.

Kelly Kenoyer: Could you just tell me what you think of these new EPA Health Advisory levels?

JD: I can say from the perspective of a scientist who’s been studying PFAS since 2005, and from the perspective of a citizen who lives in a state that has been trying to understand the health effects of PFAS on its citizens, I am very happy to see that the US EPA has moved forward with guidelines that are much lower, or with with advisory levels that are much, much lower than the previous advisory level of 70 parts per trillion. I think it tells us in the PFAS community that if PFOA and PFOS can be detected in drinking water, then those levels do pose a likely risk to human health.

KK: So yeah, I know one of the things that we had talked about in this newsroom is that there isn’t a way to test down to the quadrillionths, which is what it is for a PFOA, the advisory is four quadrillionths, basically, right? So what does that mean for actually monitoring the health and safety of drinking water like that?

JD: So that’s a tough question. And I think you might need to involve an analytical chemist, but my understanding is that when these advisory levels are set, if they are below detection limits with current technologies, then there’s a practical value that’s put into place. So it may be the detection limit itself then becomes the sort of health advisory level. If it can be detected above this level, then we know it’s above the health advisory level. But I’m not. I’m not quite sure of how all of the chemistry and technology works to turn those advisories into a practical level.

KK: So one thing that I’ve heard a lot from title is that it’s great to have these four very serious PFAS, develop these health advisories. And it’s great that the DEQ is planning to do actual regulations and water standards for another 10 to 15. But there are so many so many PFAS, there’s 1000s of them. So the concern is that this is environmental Whack-a-Mole. That’s the term I’ve heard a lot. So what are your thoughts on that issue?

JD: I think to date, there are just over 12,000 individual PFAS that have been uncovered by computational toxicology approaches used by the Environmental Protection Agency. I have been a co-author on a paper where we recommend PFAS be managed as a class. And when I speak about PFAS, I speak about management from a class perspective.

Management can mean different things to different people. Management as a class could mean dividing PFAS into different subgroups or subclasses. It’s really up to the entity doing the managing. But it’s my opinion that evaluating PFAS one by one by one is not really going to solve the problem of people being exposed to PFAS or having PFAS be in the environment unnecessarily.

PFAS are compounds that have many different characteristics of concern in common. For example, the vast majority of PFAS are environmentally persistent, they may not degrade on scales less than geologic. So they take a long time to degrade in the natural environment. Many of the PFAS that we’ve studied are bioaccumulative, so they can move from the environment into living organisms, many of the PFAS or mobile, which makes them different from other types of persistent organic pollutants. And the PFAS that we studied have toxicity. So I have no reason to think that the understudied PFAS aren’t going to exhibit one or more of those characteristics of concern. And so it seems logical that we would want to manage as many different PFAS at one time as possible.

KK: Perfect. Thank you so much, Dr. Dewitt.

JD: Yep, no problem, Kelly.

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