Event recording: PFAS exposure, bioaccumulation and associations with health effects

Video transcript

Hello everyone. It's terrific to welcome you here today to EPA Victoria’s fourth environmental science seminar series event on the topic of PFAS exposure, bioaccumulation and health effects. And really what we're aiming for today is to talk about what we do know in terms of these group of chemicals, but also what we don't know, with special guest speaker Professor Jochen Mueller who I’ll talk about later and we'll all be good Jochen, it's okay I’ll say good things about you. He comes to us from the Faculty of Health and Behavioural Sciences at Queensland Alliance for Environmental Health Sciences and it's great to have him here to share his considerable knowledge and insights; probably being the first or one of the first to actually look at these chemicals in Australia, so he's got a long history of working with these chemicals and has got a great knowledge of them.

Our event today is being held on the Traditional lands of the Kulin nation. I wish to acknowledge them as the Traditional owners and pay my respects to Elders past present and future. I’d also like to welcome members of the EPA governing board, Graham Ford and Ross Pilling, are somewhere in the audience, welcome today, and a big welcome to those who are joining us via live stream throughout Victoria, Australia and overseas.

We have a stunning 535 people joining us today online so I’m terrified the technology is going to work so for those out there in live streaming land, welcome, I hope this works for you and I hope you all get to actually see this presentation. And we also have some media outlets who are using the live stream facility as well and particularly in the Gippsland region so hello to that crew as well. A few housekeeping notes: please switch your phone to silent for the duration of the event and in case of an emergency the tones will go off, so follow the instructions of on-site staff.

So, today's series is really to discuss PFAS exposure, bioaccumulation and health effects, and I think all of you are here today and we've got such a big audience because we are finding this material all over the place, all over the country, and because there's an awful lot we don't know about these chemicals and their impacts. There's increasing concern worldwide, we know that this manufactured group of chemicals, there are some 4,700 of them, which is pretty amazing when you think about a group of chemicals. They're resistant to heat, chemical and biological attack, and when they find their way into the environment they persist and, of course, from a Victorian EPA point of view, we're finding them in soil, surface and groundwaters and also biota. So we're certainly concerned about them because we know them to be accumulated and I know Jochen’s going to talk about that and I think the main thing for us is that we actually find them in our homes and we're finding them in the human population at low concentrations as well, so this is not a chemical that we're finding in particular select locations, although we might be finding higher concentrations of them, and in Victoria we have many sites that are currently affected by point sources of contamination and then when we start to talk about health effects there's considerable debate about the health effects of PFAS and at what concentration something might generate a particular health outcome, so it's a legacy issue, it's a current issue, it's got wide spatial extent and it's something that we need to do something about. So on this note it's great to actually introduce our guest speaker for today Professor Jochen Mueller. Yeah, I’m going to say something about you first – he grew up in - sit down again -he grew up in rural Germany near a cable waste incinerator that emitted dioxins, a group of chemically-related compounds that are also persistent environmental pollutants. He went on to study the impact of dioxins and other organic pollutants on human health during a master's degree at the University of Hononheim and a PhD from Griffith University. He became a fellow of the Queensland Alliance for Environmental Health Sciences at the University of Queensland, which used to be called Entox, where he established a research group that established and focused on exposure to chemical pollutants, including novel approaches for actually assessing exposure. His team commenced work on PFAS in 2004 so he's got a good history with this particular group, and demonstrated exposure to various PFAS over the last decade. As part of his research he's led numerous national and international studies such as Australia’s national dioxin program the brominated flame retardant program, and a major study to investigate bushfire emissions and the results of which are included in the United Nations Environment Program toolkit. So it's my great pleasure to introduce Professor Jochen Mueller here today, so please join me and welcome him to this talk.

Thanks so much Andrea, thanks very much, this is a bit intimidating I have to say, I don't think I have ever really talked in front of 500 people online. Okay, now firstly research is a lot about, firstly let me also acknowledge the Traditional owners of the land and it's really great to be here and thanks for the week EPA for inviting me and I like to start off with thanking a couple of people that are on my slides. I don't know whether this is going to work, no maybe oops, so first of all there is no good research without good students and I like to acknowledge a couple of my students, Lisa Toms, Jennifer Browning and also Jake and Christy Thompson; all of them have worked with me on PFAS, and a few great colleagues, Lisa Alverez and Antonia Calafat, from the USDC and I will talk a little bit about their work.

In my title I try to cover a broad spectrum of PFAS, things what we know and what we don't know, and I thought the audience would know probably a lot about PFAS already so I tried to bring a couple of curiosities in for example I take you along the path of why do they bioaccumulate or I at the end I give you some personal notes and I’d like to say right at the start that I have to take full ownership and I may not there may be quite many people which don't share my final conclusions so it's my personal views there that I express at the end and they actually come from something that Andrea mentioned right at the start which is that I came from a contaminated site in a small town in south Germany where there was a cable waste incinerator incident and we all thought we're going to die of cancer very soon because there was high levels of dioxins around us and it scared us really all in the mid-80s and this is why I actually studied what I studied this is how I came to study environmental toxicology and now I think the scaring was worse for us than actually the toxic effects of the dioxin or the exposure and that leads actually to some of the conclusion I come to but let me go through my talk so I have an outline I will give you a very brief history of PFAS and each of these subtitles I will end up with a slide saying what we know and what we don't know.

I will try to summarise what we actually don't know so quick about PFAS’s history what they are and how we analyse them then something about exposure and pathways and routes or routes then we I take you along the path of why do they actually bioaccumulate I think this is probably what is least understood why are humans so different and we are actually different when it comes to PFAS. I tell you some good news about serum data in Australia at least for the general population and I take you a small path on the health and toxicity and then I turn this round with some personal thought. And I came out from a overseas trip last night so if I snooze off in the middle I have something to keep me awake to get back this is a simple PFAS timeline and this is actually stolen from a guy called Ian Ross who works from Arcade some of them some of you may know him he's a big promoter of something called the Top Essay and he put this together what I’d like to say here is they were invented they are old actually they are they are older than even DDT or around the time of when DDT was developed the PFAS were there apparently this was a almost an accident and they were then in the ‘50s developed into products and in the late ‘60s they were actually following a ship accident a ship fire they were turned into a fire fighting foam that's my understanding in around 2000 the first time I heard about it was around 2000 it from a guy called John Geisen in Kanan and they gave a talk at the dioxin conference and I thought what are they talking about these chemicals don't have chloride we usually only care about chemicals that are chlorinated and they are aliphatic so I was really I never thought I’d get into this I remember then czech holland thought they were quite curious it was the next person I talked to about this but anyway around 2000 environmental scientists environmental toxicologists became aware of them and then sort of a big slow frenzy started and then I think in Australia the thesis hit the fan about eight or so years ago slowly bit by bit now I also put on the bottom something about the two ways of making PFAS in general there's electrochemical fluorination which produces 70 percent linear and I come what it's linear and branch and 30 branch and there is a floral telomerisation which uses something like fluoroethylene or fluoroalkanes to make them and they mainly produce short shine even numbered chemicals okay and then we have two groups of these chemicals that we generally when we call PFAS, we say poly and per-fluoroalkyl chemicals.

I know this is probably most old stuff for you guys but I just like to when I say PFAS I mean both and when I talk about PFAS then I mean the right ones it's the polyfluorinated alkyl acids that's where PFAS and p4 is part of and now carefully said very difficult to destruct you need a lot of energy to essentially break them down and break them down and then on the on your left hand side there is the polyfluorinated substances which have these carbon stuck in here carbon with hydrogens and it makes them weaker and it's where usually they break to bits and may be the precursors for the PFAS the ones on the right side and as Andrea said they're 4738 or something like this who counted and I don't even know whether they include the branched and the linear separately or not they come in all shapes and forms and the per-fluoroalkyl acids are very persistent and the poly have a huge variety in their properties and so on and when they get bigger if we go from a c4 to a c12 or something then they become less polar less water soluble and when they have a sulphur groups the perfluoroalkalic acids when they have a sulphur groups they are more non-polar than if they have a carboxylic acid groups, which has an effect on how they behave or how long they retained in the soil on the way to for example the groundwater so shorter travel fast carboxylic acid travel faster than sulfonic acid and then there are precursors to them they have all kinds of moieties and they can be an ionic splitter ionic or cationic okay and they can fall apart or they can be transformed biologically or chemically to perfluoroalkyl acids. And chemical transformation does not necessarily predict biological formation transformation so it makes it all confusing we use this essay and I come back to this which does a chemical transformation but it doesn't predict actually what's going on in biology.

Okay just to make it confusing here let's list of chemicals from Jennifer Field and Chris Higgins’ group from Boston hanson and each of these chemicals there are numbers there in this table I know you can't read it it's not for you to read it you can read the paper but there are numbers there and these number says how many different carbons can be in this so every of these chemicals can have multiple forms with multiple carbons on the right side of this figure is when you look at wastewater treatment plants in Australia what goes into the influent of wastewater treatment plants and what comes out of the effluent of wastewater treatment plants then you see that for example for p4 there's almost 10 times as much p4 coming out of wastewater treatment plants than are going into wastewater treatment plants now there are two explanations to this either somebody chucks in p4 in the wastewater treatment plant for example by doing something funny or there is something going in that we don't see that converts to p4 now we saw the same for p4s a couple of years ago we have redone this work in 2016 on census at 100 or so 70 wastewater treatment plant and we couldn't see p4s anymore being more coming out than in now we are not sure whether our result earlier was not right but for p4 we see this sign for the sulfonic acid it's not published yet but for the sulfonic acid we just see roughly give or take what goes in comes out now there is something also going into the biosolids and I, 70 per cent of all I say is made up on the spot no but there is a is something also going into biosolids let's say 10 per cent, five to ten percent of p4s most of it is coming out we're not quite sure whether there is much p4s produced in the moment in the wastewater treatment plants.

Here's an OECD pamphlet that came out last year and it essentially says that of the 4730 p4s that that are identified about 90 per cent maybe precursors now when we cover here it says 14 with standard EPA method depends which lab you work with now you can do 29 or 37 or I think we are now up to 45 something like this different PFAS that you can measure but we are a long way away from the 4730 recognized ones and then there are other non-recognized ones this is a study we did trying to measure PFAS mobility around the firefighting training ground using a suspect screening method so it's a method that doesn't use just standards but it uses also other method it uses a mass we're looking for masses that have fluorides in it that are organofluoride chemicals and we actually could sort of identify these chemicals they have all acronyms there and the light blue the dark blue ones are the chemicals that we have standards for the light blue chemicals are chemicals that we don't have standard for and down here we look at how deep these chemicals are traveling which tells us something about their mobility all right so this is zero to two meters around the firefighting training ground and you can see that depends on the chemical some travel fast some got stuck in the top layer and we think this is because of these different properties okay now we have to say the analytical method that we used for this the extraction method of soils is based entirely on extracting p4s now if a chemical is for example a splitter ion we may not actually be good in extracting it and we can't put a standard for that chemical in because we don't know it so our analytical method is rather dodgy because we rely on an extraction method that is essentially the extraction method of p4s by the way you can interrupt me or shake your head if you don't know what you whether you know not those people on the internet okay all right and the bad news here is they are a bugger to remediate they are really I mean actually what remediation does is we are moving them forward and backwards and trying to make them smaller in the process so when they are in water in water yeah when I go to Europe I put my Aussie accent on when I’m in Australia I put my wog accent on all right.

So when they're on water we take them out of the water with the solvent separate them but then we have them in the solvent if you guys at some of these remediation sites ahhh help there was only one button to click that's how I keep you awake all right so when they are in the water we take them out of the water and put them in the solvent and on these on these remediation sites where they remediate water they build absorbent and then when we have them in soils our ideas we put them then in water where we then put them out of the water back on the solvent now this is really true this is these are the methods we have the problem is that actually in the environment the concentrations are still very low I remember when I was a undergraduate student there was a newspaper article 9 nanograms per kilogram dioxin found in the soil and my mom said hooo nanograms that must be a lot the reality is these chemicals are in the environment at concentration that is essentially point bugger all and it makes it not worth to do something with this environmental face directly so what we have to do we have to get them from these nanograms over many orders of magnitudes enriching them to ideally milligrams so they start forming again and then we can maybe make it worth to put the energy into it to destroy them that's really the goal here because there is no method and by the way there are some people who hope that we can find bioremediation that is that bugs eat them up now if you would be a bug and go through the soil and you rely on PFAS for your food you must be bloody desperate and that's the reality it's quite tricky I think there are so many other energy sources in that soil that I think to rely on such a solid bond cf I’m starving for cf now this is really unlikely anyway and last but not least they are an analytical nightmare so I’m taking you a through bit through analysis briefly now who has done PFAS analysis in the room okay good one all right no that's great so that's good because then I it's worth to explaining so we have two types of approaches to analysing one of these approaches or the main approach that we that most of you if you have ever commissioned somebody to analyse p4s has probably done a target analysis you say I want the standard EPA 20 or so these are well-defined target compounds we use LS triple quad mass spectrometer we use something called isotope dilution method we actually put PFAS dis20 into the soup into the soil into the water in whatever the sample is we put them in but they have a car they have carbons that are different mass and we can then later say we put 100 in and we found a peak that is double as big than the peak that we put in and we know what we put in is hundred then that other peak is 200 that's how easy it is it's actually all relative to what we put in you can even spill half of your sample by accident and you can still say it's double because you assume that what you spilled you spilled as much of what you put in then what you and you get a recovery and the US EPA actually accepts ridiculously 20 per cent recoveries that means you spilled actually 80 per cent somewhere you lost it and you still accepted them.

Now that's what we call target isotope dilution method it's a really good method there shouldn't be much doubt about it you … people do make errors I know and there are inquiries about these errors but normally this method works okay and then there is a second method it's the LC-QTOF method that's sort of it can do target analysis but actually the cute off the first instrument this LC-QTOF it only looks for the masses that you tell it to look and that's only if you look for 20 chemicals it's actually 40 masses because we look every chemical with two and also your isotope dilution but the right one the right method it looks tries to look for all masses it trust it sees thousands of chemicals and I show you a quickly a slide it tries to you can use it to do accurate target quantification which means you can still use isotope dilution method but it's much more tedious it takes more training of your staff it's more tedious to actually do the quantification QTOFs in the moment the best ones are probably three to five times less sensitive for the common PFAS, the p4s and p4 then the normal the most important thing is you can retrospectively interrogate your mass spectra sorry that I’m boring you with this but you can look back in time in your samples because everything is archived and you can look well now I have a new PFAS that I think about I can look back in time for this new PFAS in my archived data okay so it's the new kid on the block all the big guns in the field Jennifer Field, Chris Higgins ourselves just kidding or they are moving to do the non-target at least to some I come back to this and then there is or this is how a non-target this is actually a blood sample looking for perfluorinated chemicals in blood samples of firefighters this is how it looks these are all the peaks that we find in a certain area and it's like finding really a needle in the haystack but then we find refined our methods and we found needles we found new chemicals that are associated with that are perfluorinated chemicals that are in firefighters that nobody knew before chlorinated PFAS actually but anyway and then there is the other thing there is this top essay who's heard of the top essay let's ask the other way around who hasn't heard of the top essay okay so the top essay 4,700 chemicals PFAS now we would I actually like to close the mass balance or we would like to know what will be our future legacy problem for p4s and p4 and so on so it's a method to hit the broth with a chemical that converts it for us really fast and tries to allow us to predict what may have now it doesn't predict what biology does to the chemical to the precursors but it does predict reasonably well probably what the chemical conversion is it's called the top essay developed by Horwitz and Satlack and people use the top essay at least to some extent using typically it's used with the target analysis and that's where it predicts how much PFAS is formed so you do a sump you analyse it for p4s let's say and then you throw in the do your top essay and then afterwards you analyse the same sample again and you look before and after and you will find out whether you had formed new perfluoroalkyl acids from chemicals that you actually don't know now the great news I think if we want to do the top essay we want to actually know what were the precursors that occurs because that's what we want to regulate that's what we want to take out of the system so for this you actually have to do the top essay with the cute off the non-target you have to see what has disappeared since we looked before and identified it very quickly one slide I think one slide total oxidizable precursor top essay might take of it was originally developed for aqueous matrices I think some ambitious Queensland regulators in the room no just Tony I didn't mention names some regulators have broadened that application to other matrices that maybe actually that causes a bit of headache because it's quite tricky to control this it does not close the mass balance and I think it's really a tool for us to understand it better to regulate based on the top essay personal opinion maybe that's a little bit early I think for aquatic matrices great I think for some other matrices it might be tricky so my first slide this was a bigger sort of piece I think we need inventories for what PFAS we are actually releasing and we should try to get a hold of past inventories we have to do more about transformation and what chemicals transform to what and how fast I think we need routine sampling methods as much as routine analytical methods and I think a lot will happen in this space and we need to understand something about the mass balance what is actually out there what do we bother do we bother about everything it takes a lot of effort second part okay so exposure sources and exposure types and routes so for this I try to make a few new slides I hope they work actually so when it comes to exposure sources and exposure types and I really call it both we have first of all these occupational exposures and we mentioned particularly fire fighting foams we all know that has been a source of exposure for example to firefighters and then the second thing I think that a clear one is use of consumer products use of consumer product it's actually not really well understood I come back to this when I show you our serum data because I think that has played a big part of why we see the levels decreasing and then we have these exposure routes that are indirectly in exposed communities we're really dealing with the use of firefighting foams that led to contaminated drinking water and contaminated food and contaminated dust whereas the consumer products have stayed the same we know that PFAS is in the water actually we did this study close to 10 years ago as Jack Thompson’s PhD and we analysed drinking water from around the country by now there should be much more data actually I don't think anybody has collated them but I think there are efforts to collate them but you can have now a much more comprehensive data set from Australia where PFAS has been in the drinking water this was an old study where we found that on average the p4s concentration was about 1.6 nanogram and the p4 concentration about a nanogram per litre and we found that almost all size had one of the PFAS that we could measure in those days we did go very low we got it we did analyse in our report in the sub 0.5 nanogram per litre and at the time we did the backwards mass balance model where we estimated from what we find in people back what that probably means in intake and we estimated that drinking water at those levels even at the highest contaminated sites contributes only to about 10 per cent of the total PFAS burden PFAAs in food they can be found in food Phisants did a study they actually found it only in very few foods in I don't know whether they did another study probably some of you in the room know this much better but there are overseas studies Annie Schechter in Texas did a big study on PFAS in food he collated a number of food found the highest level of some of them in olive oil there are other studies in Europe I rem I remember there was a bit of kerfuffle maybe almost 10 years ago about PFAS in potatoes but the evidence that food is an important exposure pathway comes in part from questionnaires and people where for example it's shown that people who eat more fish there's a correlation between higher fish consumption and PFAS in blood I think food is more difficult to assess because of the variety of food we are dealing with I think food was also a problem because do we measure the food after it's been wrapped up and unwrapped or do we measure the food fresh we done a big study with New South Wales food what I can tell you is in our study when you cook fish the normal way you're neither adding PFAS unless you use a really silly pan and you're not destroying PFAS you're transferring some of the PFAS in the cooking oil or in the water but you're not actually but it's very small the PFAS mass balance in the cooking this is a study of Matt Taylor I have to mention it there is no distract there's just a paper coming out of Turkey where they cooked fish for 20 minutes now Matt Taylor said if you cook fish for 20 minutes you don't eat it anymore but maybe there is a particular dish in Turkey but anyway they said that the PFAS level in the fish decreased by almost half that's just been published we couldn't see any of this any of this in fish that we would have loved to eat okay in terms of occupational exposure and I use these simple sorry I use these five introduced before five symbols occupational dust food consumer products and water and so I think in occupationally exposed people we think it's something to do with occupational exposure we actually don't know how certain firefighters were exposed we did a study on firefighters with air services it's published where we showed that the only thing that we could link to high serum levels of p4s was that the firefighters have worked before 2004 at air services all those that were later than 2004 didn't have higher levels and we think this is because before 2004 they used light water which was a PFAS-based foam when you come to places that have a contamination source we see something really different actually when you come to some Australian contaminated places you find this redistribution of PFAS and you see this in consultancy reports and we wrote one paper about it but when you actually go there you see that they may have stopped the use of groundwater for drinking water but the groundwater is still used for sprinkling the garden and for doing all these other things and I remember the first time I came to this one town there were sprinklers going it's very arid sprinklers going the dog was playing in the sprinkler and the kids were catching the dog under the sprinkler and I thought gee this is really difficult how distribution of chemicals and exposure pathways work and we really don't understand this what we understand is that the PFAS in these communities when you look at the size it's elevated essentially throughout their product now I don't have actually control samples but the control sample here should be essentially near zero and when you look at particular in this case some of the beef and some of the other samples it's really quite astonishing how high the concentrations were and this I think where Roger Drew here in the audience he actually does a study how long does it take to clear the PFAS out of these cattle it's really interesting that a cattle clears the PFAS much much faster than a human being so that's although the body mass is much much greater which brings me back later to the bio accumulation so if we talk in exposure in communities with commander community with contaminated groundwater I think water and food are the big drivers dust maybe food mouth contact so this is sort of a conceptual picture when it comes to the general population we think it is food and maybe consumer products there is a study from Winkens, Kirsten Winkens from Ian Cousins’ group who suggested that actually consumer products contribute about well actually precursors contribute about eight to ten per cent and when it comes to babies although PFAS are not very lipid-soluble they are found in breast milk and actually breastfeeding does make a contribution I didn't think this really first but the evidence the latest paper suggests that there is some contribution from breast milk. so what we don't know we really struggle understanding exposure routes and that makes it actually hard to do the interventions to make sure that we are cleaning our act up there has been a recent paper that showed that when you stop when you give advice people do go down faster what's the paper I have to think of the author of the main author he's one of the C8 studies from the epidemiology group comes back anyway so what we don't know is current advice in communities and occupational cohorts actually working and this is why in the moment we have done only usually one cross-sectional time points for these communities so for most people we only have one point and we I think we need other points to really see this this is working we really don't know the role of consumer products and we don't know the role of precursors so half time a bit more than half time but to keep you awake why can't you use beef stew as your password it's not Stroganoff enough yes that's right great response Dad joke Tony told a Dad joke in the break but I can't get it back about tour choices okay all right are you with me still? Next thing is a little bit dense but possibly the most interesting one okay I’m doing a bit of pharmacokinetics have you ever wondered why PFAS bioaccumulate nah who cares why do some bioaccumulate okay so in in pharmacokinetics they talk about this adme absorption distribution metabolism and excretion and I take you briefly through this in humans okay as much as I can so we know PFAS when it's consumed is fairly well absorbed and there is a decrease in absorption with chain length now the absorption through skin is low depending on the ionisation state it can be high if not if not ionised but it's usually ionised so it's really not usually considered the problem and these chemicals also absorb in plants and worms and just one little slide from our own work this is a PFAS contaminated soil when we stop when we reduce absorption by mixing the soil with something that absorbs the chemical in the soil or that essentially reduces leaching it's called a chemical called rembind when we do that the concentration in the leachate decreases very much by orders of magnitude by two to three no I’m sorry this is log scale so if you go one level down it becomes 10 fold down so it's a big decrease so 99.9 per cent of some of these decrease for p4s when you for the more absorbing chemicals when you do that what happens when you put this when you put worms in the soil when you then you also see then when you put when you inhibit the bioavailability then you get also much less uptake in the worms so this means that absorption is leech bioavailability is really directly related to the availability of the chemical or the desorption of the chemical and the same in grass so very short story if you limit if you bind the chemical in the soil it becomes less mobile and it becomes less available into grass and it becomes less available into worms and it's a matter of what's your chain length of your chemical so here I plot from c4 to c12 carboxylic acids and here is the sulfonic acid I know I’m challenging maybe a little bit now this was absorption I’m now coming to the distribution and storage so PFAS how do they distribute and how do they store in our bodies they are non-covalent bound that means they are not forming a chemical bound chemical binding with the plasma and the lipo proteins in the plasma and there is this balance between what is bound and what is free and a very small portion of the PFAS that is in your blood is actually in the free form so when you find the PFAS in your body it's in protein-rich tissue such as your liver your kidney and so on and we think we toxicologists think that the bound PFAS is not active but actually acts as a reservoir and then there are these organic acid transporters which I come back to and on the right side there is this binding constant which is in the paper from nunc and hunger pool in Switzerland where they show that there is a certain chain length where the chemicals bind most tightly and these are about eight to twelve so these chemicals bind more to your protein that means they are less excretable they are more caught in your body so that's about the distribution and storage in your body when it comes to metabolism of the chemical the per-fluorinated chemicals we think do not degrade at all there is a chance that the polyfluorinated chemicals actually form the per-fluorinated chemicals form from the polyfluorinated chemicals this is again what Winkins suggested about ten percent of what's in your body comes from polyfluorinated chemicals and it's also put in a model from metal and again the Swiss group they put this even in a model this transformation and Chris Hickens in the US is in the moment doing a study particular on this transformation because essentially we have banned PFAS and p4 so now we're dealing only with the release of potential precursors now if we get exposed to these precursors will this result in future transformation in our body to stable PFAAs? Now the big trick and I think this is what really I didn't appreciate until a year or two or three ago it's about the elimination this is the trick this is where humans are seem to be really different so people write very easily about this PFAS are then reabsorbed in the kidneys so that this fatty acid transporters that when you excrete so essentially the PFAS gets transferred into the urine but then there are these really very efficient transporters that transport the PFAS back and they're not only in your urine they're also actually in your guts or in your intestine walls and there is multiple evidence in this for example there is a study where they gave somebody or they looked at cholesterol lowering drugs where they showed that these cholesterol lowering drugs actually which work on the fatty acid transporters I think in the gut wall they also inhibit the re-transport of PFAS and you have more excretion so essentially people are thinking now of the idea whether there are medications that we could give to prevent the reabsorption and speed up the excretion okay now we're falling all asleep but essentially what I’m trying to say bioaccumulation is complex and where humans are really different is probably on this reabsorption bit where because I think blood of animals is very similar in terms of protein composition so it's this we are not eliminating it as efficiently yes I think I skipped this I think I summarised this but there's so and I said all this there's also something about this on sex differences particularly in rats now are we looking for the right PFAS? Now there are other PFAS that are actually accumulating this is for example these PFAS that we found in firefighters that are not the conventional p4s there is a chlorinated p4s there is a ether based perfluoroalkyl substance and there is recently a paper from China which showed bioaccumulation of a whole range of other PFAS so there is not only these PFAS and p4s that are bioaccumulating so that you will hear probably more from the space of whether these other chemicals are what we don't know about bioaccumulation the difference in accumulation in different people is that to do with our differences in ability to excrete PFAS? So there are people that have extremely or very low PFAS levels it seems is this because they are less exposed or is this because they are more excreting the chemical and is it feasible to speed up this elimination can we use drugs we know actually blood donors have lower PFAS levels hemochromatosis patients we did study some hemochromatosis patient have lower PFAS levels and why do differences species different species show such great differences and then we probably in the future will hear a lot about the role of precursors okay the easiest part of my talk is actually jumping from this bioaccumulation to the good news the serum study so we've been doing since 2002 a study initially funded by Sarah Broomhalt's predecessor Chris Mobbs sorry Chris Mobbs and colleagues what they wanted in 2002 they asked us to look at what is the average concentration of dioxins in blood in Australia and for this study initially we collected 10, 000 blood samples from surplus pathology samples and we pooled them according to age and postcode and gender and we created 100 pools but in short it was such a successful study that we decided we do this every two years and so here on the right you see this timeline where every two years and the s stands for a particular study every two years we collect nowadays 2, 400 blood samples cross-sectionally leftover pathology samples and we look at a whole range of chemicals in those dots and initially Antonia Calafat analysed them all for us for free because she thought this was really quite curious yeah and this is a set of data just for PFAS so what do you see here the red are the 2002-2003 samples that were collected then and then the green and so on you can see and at the bottom you see the 2016-2017. Okay I should have explained this graph a bit better on the x-axis you have h every dot is 100 sample on this figure except some of these dots on the left here these green dots because we didn't have that many children and so what you see essentially is the levels are decreasing so you can see that for example for PFAS the PFAS levels in the Australian general population now all the older people are put into one big box for each of these years and you can see that the PFAS concentration Australian population has decreased by 85 per cent or so since 2002. That's a brilliant news so this suggests that exposure has decreased by a substantial amount interesting hexa-sulfonate has decreased much less and it's funny with this non-carboxylic acid it actually had a peak in 2008 so we don't actually understand yet what led to this different time pattern and we use this data to with Ian Cousins and his team who are modellers and Matt McCleod we have used this to backwards estimate from the sum of all these data to backwards estimate and ana is a similar data when was peak exposure of PFAS in Australia and this suggests that the best fit model suggests that peak exposure for PFAS was around ‘95 early ‘90s, ‘95 so probably somebody knew maybe we should slowly replace what we do we change in consumer products and before us environmental scientists actually became aware of the PFAS now this is a model but there is other evidence to this that so all we can see since 2002 the levels of PFAS in the population is decreasing relatively rapidly by the way here I drew a a line and this is suggests that our current intake give or take from this model is about one nanogram per kilogram body weight per day roughly we use this data to estimate what is a high level in the population so we use we assumed distributions and for these distributions we used the national health environment nutrition and the national health and environments health and nutrition environment study and Heinz data and they have they have individual data they do thousands of people every couple of years and from this we get a distribution or skewedness of the distribution and we done it also with other with the Belgian group we looked at individual general population data and looked at the distribution and calculate what is the ratio of the 95th percentile to the mean and we just redid this for the nine for the 2017 data as well and just submitted this but this is the old data and then we use the statistics from this from the data to estimate whether people are higher or not whether people are normal so for example here we compared the firefighters that we looked at in air services whether they are high and then we looked further what differentiates them and here I don't know can you see this mouse okay all right you can see that if they were less than 10 years in the job they were normal only if they were more than 10 years in the job and so we used the population data to do this by the way we also looked at health indicators in these fire fighters such as cholesterol which is associated with PFAS levels we couldn't see anything in in these fire fighters but there's really relatively few data so what we know actually with the serum data levels are decreasing we don't know why they decreased from the mid-90s we don't know it for individual people how they decreased we are hoping that we can estimate in future peak serums levels and I think we need to look broader about new per-fluorinated chemicals sort of summarising the serum I’m slowly winding down so now I’m at the health impacts now this is the area where I feel least comfortable to talk about because it's and that's the crux of course what are the health problems what is the evidence what do I what do we know about it I there are other people here in the room which are probably better qualified to talk about this but in brief we measure health effects using epidemiology and toxicology and epidemiology tells us a whole lot of things the c8 study is probably the biggest study more than 60,000 people many elevated and they found evidence for increased serum lipids uric acid altered thyroid ulcerative colitis they found two cancers bladder cancer and kidney cancer I think and Phil Corchon is talking about a lot about immunotoxicology and immunisation other studies don't find the same thing but they are not as powerful certainly as the c8 study and now maybe many confounders like to remind you correlation is not causality there is some reason why if you have higher cholesterol you could also have higher binding capacity in your blood for PFAS so there could be not causal and so on and then there is evidence from the toxicology in animals I mean if you look at the molecule you see that this looks like a fatty acid in broader sense and in in effect fatty acid metabolism so there is a weight of evidence type thing so there's lots of evidence I think that the trouble is there is no PFAS-specific disease and once there is no PFAS-specific disease it becomes extremely difficult to find links between exposure and I think this is the real challenge that we have to explain to communities that our tools to actually relate chemical exposure to effects are pretty bad they're enormously bad and it makes it so difficult and just because we don't know and the interpretation of this information that we don't know is so difficult because there are some of us that interpret this as Oi, that's bad and others say what there is no evidence and this controversy makes it so hard so I think this is what we have to learn to communicate so the current estimated background exposure I mentioned before is about one nanogram which is well below the health-based guidance value of that Phisance put out of 20 nanograms per kilogram per day but the proposed new health-based guideline value for PFAS from Phisant is 30 nanograms per week and I know is this now out I think it's out it's out as a draft sorry okay so it's very this is very close to current intake and the Germans have published a reference value and in this new paper which we just submitted we find that the German reference value for which they say there may be or there are they there may be health effects it's five nanogram per milliliter which is roughly our Australian current PFAS average and it's well below the nift 95th percentile in our Australian population now that's a little bit we really struggled how to put this actually in this paper how we discuss this we actually predict that in about 10 years we will be with our 95th percentile below that what we don't know health effects is health affected and the causality and mechanism I looked at ATSDR site last night and it in some of the advice to the people they say we know that PFAS causes health effects we have said in the past we don't know whether PFAS causes health effects I don't know it's not something for me to und . . . but if we think PFAS causes health effects then we should seriously consider whether we need interventions and we know that we have intervention strategies that are actually easy to implement at least in the first cut we can go blood donating if we donate blood we reduce our PFAS blood levels much faster than if we don't donate blood and everybody considers donating blood as something that is non-invasive or not but I don't propose this I just say if we think it causes health effects then the consequence would be that we should think about should we do something about it so far no government in the world as far as I know advocated to do something when you have high blood levels so if we don't do something we must think and then we need to learn how to communicate uncertainties to people how do we interpret uncertainties I think this is the trickiest and here comes my wrap-up uncertainty actually causes stress and PFAS contamination in these communities is objectively a stressful event and there are all these effects in these communities they are worried about their health but they are also worried about financial loss and the future of their of their community and they are frustrated and even frustration causes stress and stress is unhealthy and I think I made this I recently listened to podcast about depression and there was a big discussion about lack of control is associated with depression and I think what in these communities is happening is actually there is a lack of control to some degree firstly they are not responsible for the contamination and then they can't do anything about it it's so out of control so and all this causes emotional responses and physiological I don't have to tell you it's a very obvious one I mean I’m dwelling now in social science which is no area but my suspicion and is that the uncertainty stress causes a bigger effect on health at least a more defined effect on health than the pfa's health but that's a wild suspicion actually let's okay I take this back sorry I take this back I think what I wanted to say is we better understand the uncertainty stress than the direct PFAS toxicity on health I think that's what it is we I am not saying that PFAS doesn't cause health effects it's just really difficult to measure this so what this is I think my last slide what we can do is we can try to reduce stress and help to gain control I don't know how but I think this is what we have to try and support these communities I think we also want to do everything to reduce exposure we want to get this whole thing under control we want to educate about risks I think education reduces stress understanding that uncertainties by themselves is not a risk I come from university I like the independent independence if we are worried maybe intervention maybe even intervention reduce I don't know look this research relied on so many people I put this last night together on an airplane from Europe I probably forgot a lot of people in this I don't know but a lot of people have helped me better understand PFAS and helped me to know that I have no idea about it actually so thank you very much

So we've got some time for some questions from the audience

so have the manufacturers altered the way that they sell these products into the marketplace say like in 1995 seeing that correlation in the dip in the blood serum levels?

I don't know the answer to that sorry I suspect I mean even the way the PFAS were produced has changed and I’m sure the since the awareness is there it's a much tighter system I don't know but I don't know really the answer to your question

Hi I’m Michael Abramson from Monash I really enjoyed that talk thank you so much there was a time of course when doctors recommended bloodletting for just about everything so many of us would probably be reluctant to go back to that but it is certainly an interesting suggestion I just wanted to ask about the human biomonitoring program given that they're pooled pathology specimens many of these people may have had some illness was there a measure for example to exclude those with known renal or liver disease?

No. Short answer actually in 2002 before we started using pathology samples we did exactly that but for dioxins we collected 400 samples 200 or 400 I forgot they were from pathology random samples and then we had the same amount postcode age and gender matched that were insurance samples that were for changing insurance so we called them healthy versus sick and we did this for dioxins and I think PCPs and we found no difference between the two groups and we recently did the same thing again because we couldn't find our 2002 samples anymore we did the same thing again recently and we couldn't find any difference for PFAS and p4 we did find some differences for hexa-sulfonite but we are going to redo it to check that whether that is sticking okay but a good question thanks we get asked that question by the why how do you know you can use pathology samples whenever we publish any of these leftover pathology samples

Thank you for very interesting and enlightening and honest talk I just wanted to ask a question you know I’m a biologist a couple of questions one is does it go more in the blood cells than the serum are they bound yeah are PFAS bound more in the blood cells than in this blood serum because of the proteins and secondly you know there's a controversy about bio-magnification of food chains Jochen from your understanding of the chemical itself what side are you on is there bio-magnification like in the chlorinated chemicals or would you say that it's just eliminated and therefore it doesn't sort of magnify up food chains?

Hmm, I mean we measure it in serum but I assume that has the protein lipoprotein in it the way we get it I don't actually know the answer really to your to your first question I think the biomagnification is much less I mean biomagnification is something to do with KOW typically okay octagonal air water partition coefficient of course this does not work for these chemicals so I think it's here much more a question of specific species it's actually quite weird what chemicals have more PFAS and than other for example shrimp in Williamtown were I think crustaceans were higher and it I think Matt Taylor and Carl Bowles suggest this is to do with benthic but I don't know I don't actually know the answer to both of your questions very well has anybody got an easy question roger easy questions your question always easy.

Do I have to press anything on this? No, in relation to the first question there's been several studies looking at the distribution of PFASs within blood and they do not partition into red blood cells and so that's one of the reasons why people concentrate on measuring serum or and or plasma I think you're right Jochen, in that the key between the distribution and accumulation in species relates to the transport proteins of the organic acid transport proteins oat and oat pea but also in the fatty acid binding proteins the binding to serum protein most of it occurs with abdomen but floating around in the in the serum are transport proteins which are actually used by cells to accumulate or take up materials and I think that that's where or how primarily these things are getting inside cells.

Any other questions?

Great thanks very much eric and Tony Merritt from New South Wales Health so you there's I could have lots of questions but you just pick one you were talking about the health impacts from the c8 study and my understanding there that was p4 and in Australia we're largely dealing with p4s so I just wondered if you'd make a distinction between those two from all that you've had experience with so far in terms of kind of likelihood of health impacts.

I don't think there is enough real data but again this is beyond me you shouldn't ask me questions that I haven't covered in my talk. It's what I tell my students at the start of the lecture don't ask anything outside but I think Roger has the answer to that, Roger?

I think it's very easy for people especially the press in the lay literature and dare I say for regulators to talk about PFASs as PFASs do this or PFASs do that or they might do this or might not do that in fact I believe PFOS and p-foa are different enough in their toxicological and health profiles to consider them as two separate chemicals yes they do have overlapping toxicity and overlapping health associations but as I said I believe there is sufficient evidence to consider them as two separate entities.

Any other questions?

I just thought I’d make a point that in the environment in Victoria there's very little p4 being measured so we're certainly getting more of the PFOS and PHFX not much of else either so that the two that we would be concerned about would be PFOS and the sulfonates

Yeah, watching that we put to you on their behalf given limited resources and what you know so far how do you identify where we actually need to put our effort into where we need to test for higher concentrations and where we are unable to actually identify exactly where it's coming from how do we hope to control the future contamination if we don't know where it's coming from?

Or yourself

I think that's a question for you or for Roger

career limiting question there on my behalf

okay well I think many of you know that we've been doing a lot of work in Victoria in terms of understanding the spatial scale of common PFAS in areas that are not contaminated because remember we are working with areas that have got point sources and that's quite different so we've been trying to understand the concentrations they're not background but areas around communities in soil sediment and freshwater and we've also been doing some work in biota and so that is actually helping framing our assessment of exposure because we are generally seeing that where we've got populations large numbers of people and sectors that we have increase in those PFAS the other thing that's interesting though is you talk about drugs to try to eliminate more PFAS but if wastewater treatment plants are a source of PFAS in the environment we wouldn't want more PFAS in wastewater treatment plants would we oh if we get them out of our bodies

yeah but then they go into the effluent Jochen no that's not no so anyway

Okay so clearly we have another question go Roger

I actually have a question that Jochen can answer. In your serum studies Jochen you've demonstrated a decrease in exposures and decrease in concentrations in those pathology samples or in any of your samples have you done any correlations between the clinical chemistry total cholesterol triglycerides and the other information?

Pathology samples we can't it's all pooled because we rely on deidentified leftover pooled so it's that's bound by all kinds of ethics you know so we we've done it in the firefight we've done it in individuals we do uric acid cholesterol we actually look at what other indicators but we haven't found but our numbers are far too small so each dot on these serum samples was 100 people or 100 samples in in one pool

Even though your samples are small in those cohorts have you seen any correlation with any of the clinical chemistry?

We don't do clinical chemistry in those

in your firefighters

okay we have not seen the clinical chemistry going into the direction that you that the literature suggested so I showed one little figure and this is published that shows that there was no increase with cholesterol for example.

That’s what we have found as well but again we've got very small numbers

I think firefighters are a particularly interesting group of people they are they're actually body mass index is not a good indicator for their body shape I if you know what I mean you know they are really sporty

Okay, we’ve got time for one question. Okay any last takers before we finish this session?

Okay on that note I’m going to stay there I’m going to thank my colleague I think you'll all agree that we certainly have had some really good information about what we know right through from measuring the various PFAS exposure potential for health effects and some of the challenges that face us in the future please join me in thanking Professor Mueller.

So we have this we have another environmental science seminar series for May please have a look for when that comes up again and I look forward to seeing you again. Thank you all for your attendance.

Event date: 18 February 2019

Per-and poly-fluorinated alkyl substance (PFAS) contamination is currently of major environmental and public concern worldwide. Due to their wide use, environmental persistence, and chemical properties PFAS move easily though the environment and bioaccumulate in the food chain. All of us are exposed to small amounts of PFAS in everyday life. This is through exposure to dust, indoor and outdoor air, food, water and contact with consumer products that contain PFAS, such as outdoor gear (such as waterproof clothing), new carpets and cookware. 

Understanding the chemical nature of these compounds is critical for both establishing sources of contamination, monitoring and informing remediation as well as understanding impacts on the environment and public health. As a regulator EPA is working on a number of projects to understand the spatial extent and magnitude of PFAS contamination in Victoria. 

For this Environmental Science Series event, Professor Jochen Mueller of University of Queensland joined us to explore the knowns and unknowns of PFAS. He provided background on the current knowledge about exposure, bioaccumulation and potential associations with health effects. 

Speaker bio: Professor Jochen Mueller

Professor Jochen Mueller grew up in rural Germany near a cable waste incinerator that emitted dioxins.  He studied fate and exposure to dioxins and other persistent organic pollutants during a Master’s Degree (University Hohenheim) and PhD (Griffith University).

Professor Mueller became a Fellow of the Queensland Alliance for Environmental Health Sciences at the University of Queensland (former National Research Centre for Environmental Toxicology (Entox)) in 1997 where he established a research group that focuses on exposure to chemical pollutant including the development of novel approaches for exposure monitoring. His team commenced work on PFAS in 2004 and have demonstrated that exposure to various PFAS has substantially decreased over the last decade(s).

Professor Mueller’s work has received support from ARC and numerous industry partners.

Speaker bio: Dr Andrea Hinwood

Dr Andrea Hinwood was appointed as Victoria's first Chief Environmental Scientist in 2017.

Dr Hinwood is an accomplished environmental scientist with specialist expertise in environmental exposures and human health.

Dr Hinwood was previously an Associate Professor at Edith Cowan University and held appointments as a member and Deputy Chair of the Environmental Protection Authority of Western Australia and a sessional member of the State Administrative Tribunal of Western Australia. 

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Reviewed 3 September 2021