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FRTR Presenter: sure that'll work. So next speaker is Jason Condor, and he's a principal at Geosyntech

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FRTR Presenter: environmental toxicology risk assessment, contaminated sediments. Environmental chemistry is his expertise published, and I'll let him talk more than I will. He's a remote right.

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Jason Conder: Yes. Can you hear me? Okay.

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FRTR Presenter: Yes, I can see you too.

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Jason Conder: Great, excellent.

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FRTR Presenter: Take it away, King.

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Jason Conder: All right.

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FRTR Presenter: Yes, Jason, feel free to share your screen.

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Jason Conder: I am doing that now.

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FRTR Presenter: There you go!

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Jason Conder: Okay, does that look good? Everybody.

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FRTR Presenter: It's great!

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Jason Conder: All right.

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Jason Conder: Well, thanks to Jason Spiker for a great setup. So this is the second part of the Jason and Jason show on pfas ecorisk, and, as Jason mentioned, I'm going to take you into a deep dive on some of the specifics around pfas eco risk. And you know, Jason did a great setup on what Ecorisk is.

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Jason Conder: If you learn nothing from what we have to say, you know, at least take home this, that we can do eco risk for pfas. You know, we're not starting from ground 0. We have a lot of great tools.

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Jason Conder: Yes, there's uncertainty. It's complicated. We're all working through it. But we can make Eco risk decisions at sites, and again

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Jason Conder: try not to do as Jason put it from Clint Sutter's quote, not to do stupid things.

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Jason Conder: So I'm Jason Condor. I'm a Phd environmental toxicologist chemist. I've been working with the Navy Dod as a consultant for more than about 15 years. I've been working on pfas since about 2,005, very early on in my consulting career, doing a lot on environmental chemistry, risk assessment toxicology. I've done a lot of work with us. Dod

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Jason Conder: Pfas issues over the years, including a guidance, frequently asked questions. Document. I have several ongoing risk assessments for pfas sites in the Us. And abroad. And I'm actively working when I'm not doing site-specific work. I'm doing pfas risk and toxicology, chemistry research projects mostly funded through certip and Esdcp.

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Jason Conder: So my talk today, I'm going to kind of give you all a little bit of a preface on Pfas Ecorisk. Talk about conceptual site models for Ecorisk at sites.

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Jason Conder: Go into some of the planning that we do for Sarah's and Vera's get into the nitty gritty of exposure and effects. Calculations. Things like that. I have a case study on a site and then wrap it up with some conclusions. Let's talk a little bit about just the basics of

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Jason Conder: pfas

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Jason Conder: real quick. Well, you know, I think you kind of get

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Jason Conder: the gist of it already, probably echoing a lot of what folks have said today, you know, at pfas sites, off-site issues tend to be most important for risks, especially so for eco, you know, we do know that concentrations that we're detecting out there can trigger risk-based concerns.

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Jason Conder: You know, background ambient levels of pfas in the environment is a huge challenge for all these sites. Pfas is

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Jason Conder: detectable just about everywhere. There's a lot left to learn, you know, Jason and I. You know one of the things we always tell people.

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Jason Conder: We don't know everything there is about pfas. You know

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Jason Conder: the 2 of us as well as the just scientific community in general. There's lots to learn, lots of uncertainties, lots of unanswered questions.

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Jason Conder: Most of what we know comes from studying Pfos and Pfoa. That knowledge base is growing. And you know there's again 2 of the families of Pfas, the Pfcas, the carboxylic acids, and the pfsas, the sulfonic acids.

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Jason Conder: So again, most of what we know comes from those 2 families and those 2 compounds

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Jason Conder: in particular. But you know, again, we're working through site-specific risk assessments. Now, we're making decisions. We can't wait for a perfect understanding of all things, pfas

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Jason Conder: or final directives or rules. There's no 10 Commandments for Pfas risk assessment. We're learning as we go along, and we do the best we can with the best available information. And I think that's really all you can ask of a risk paradigm. We're still learning about Pcbs and metals and other things that we've been working on for decades. I suspect that will be the case for pfas for a long time to come.

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Jason Conder: you know, echoing what Jason said. You know.

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Jason Conder: we shouldn't panic. Pfas obeys the laws of physics. They're not magical chemicals. We know we're getting better at modeling and predicting what's going on with pfas. We're understanding the chemistry, more, the toxicology more, you know. Again, Paracelsis. Don't forget the dose makes the poison. This is especially important to remind stakeholders and site managers and folks.

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Jason Conder: just because we can detect something doesn't mean it's a problem. Our analytical chemists

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Jason Conder: have gotten extremely good at picking up trace levels of these compounds in all kinds of environmental media.

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Jason Conder: We don't have to reinvent the wheel for risk assessment. Again, we have a good paradigm for working with emerging chemicals and standard chemicals

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Jason Conder: looking at exposure and effects. We do not have to reinvent something just because these chemicals may not behave exactly like a PCB. Or lead, or something that we're used to working with.

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Jason Conder: you know. Again, we can still use risk assessment paradigm here to make good science-based decisions at sites.

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Jason Conder: And again, if you learn nothing from my talk. Please take that bullet home with you again. We we can. We can do this. It's not perfect, it never will be. There's going to be uncertainties

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Jason Conder: but it we can use this process.

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Jason Conder: So some basic ecorisk resources. And I believe these are hot linked in the presentation. If you're able to download it and look at it. But you know it's rapidly growing. But there's a lot of good recent compilations. Some of the work that certip has put together on ecotoxicity at pfas.

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Jason Conder: There's been some projects, workshops. There's all kinds of great tools and trainings available at the cert website, you know. I'd refer you to a document I wrote, and then one by Craig Devine, in 2020, where we basically have a lot of good basics on Picotox at Pfas.

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Jason Conder: There's a special issue number 2 there of integrated and assessment, environmental Assessment and Management journal in 2021. It has a series of papers on looking at Eco risk assessment resources for pfas. So please look at that number 3. There, there's great chapter 9 of the Itrc pfas

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Jason Conder: guidance on site specific risk, assessment covers eco, and a lot of great things in there. And that's an evergreen document that keeps getting updated. So we're continually adding and improving that document. And then, for there's some Navy

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Jason Conder: issue papers on pfas, screening levels and other resources from the Navy, and you could bug Jason Spiker about getting a hold of that that's available as well. So there's some things to start with. You're not starting, you know, at square one here. There's a lot of good resources out there and thinking for how to do Ecorisk at sites.

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Jason Conder: So let's get into some of the 1st steps of thinking about pfas at a site for Ecorisk, and you know Jason covered a lot of the basics. But let's talk a little bit about how those basics apply to pfas in general.

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Jason Conder: Most of the places that we're dealing with pfas risk assessment. It's an a triple F site. This was this presentation again, was developed for the Navy Writz program. So it's very heavily focused on a triple F sources and and details.

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Jason Conder: And you know, typically what we have at a site, there's a source it's released to soil gets into groundwater at an aff area. But for the most part, at these a period areas, they're right next to a flight line. They're an airport. They're in an area that is a managed

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Jason Conder: lawn. It's not a lot of great habitat for eco, and if you don't have habitat, it's less of an issue for Eco exposures, but because pfas are fairly mobile, they can get into the water. They can get down gradient in aquatic systems, creeks and

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Jason Conder: rivers and streams and things like that. You know, we can have groundwater carrying pfas away where it might emerge and cause issues in, you know, existing habitats that may be far removed from their

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Jason Conder: flight line. So that's an important thing to think about again. Most of where we're focused at these sites is, you know, a mile off the a triple f pad or down gradient in a creek, or something like that.

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Jason Conder: Another big thing for pfas bioaccumulation exposures look like they're really one of the most important things to think about. Ecorisk

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Jason Conder: pfas can bioaccumulate in aquatic terrestrial food webs. We can have some pretty strong bioaccumulation signatures in aquatic life thinking about fish and invertebrates and aquatic plants based food web in the terrestrial zones. We can have bioaccumulation into soil life, especially bioaccumulation into earthworms insects

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Jason Conder: as you can see there on the right. There pfas accumulates pretty readily, and plants just pulls the water and ends up often in leaves and fruit and stems

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Jason Conder: to rather high concentrations.

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Jason Conder: What is interesting about pfas? And what is a nuance compared to typical organic compounds is that pfas tends to bind to proteins.

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Jason Conder: not lipids. So if you think about Pcbs petroleum compounds, organochlorine pesticides, the usual compounds that we're usually working with in terms of bioaccumulation.

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Jason Conder: those tend to like fat, and we built up models

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Jason Conder: over the last decades to understand that. Well, we can't really use those directly for pfas. We're having to modify them. Tweak them come up with new approaches. But again, we can work with these sorts of models. We can develop these tools. We do not have to, you know. Again throw the All risk assessment approaches out. We can use this type of stuff for working with bioaccumulation, and I have a few slides that get into that

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Jason Conder: some other generalizations on bioaccumulation. Again, bioaccumulation is important.

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Jason Conder: There's some kind of general rules that we've observed from studying bioaccumulation in plants and animals over the years. One of it is that chemical size affects bioaccumulation.

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Jason Conder: you know, looking at the Pfcas and pfsas, this is an example of Pfbs, a very short chain sulfonate. Pfos. Everybody knows that one's right in the middle, and then Pfdos is a longer chain at the bottom. There

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Jason Conder: the shorter compounds tend to bioaccumulate more in the plants.

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Jason Conder: The longer compounds tend to bioaccumulate more in the animals, so

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Jason Conder: kind of in the either end of the spectrum. We have bioaccumulation concerns in plants or animals. So that's important to consider conceptually

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Jason Conder: another issue to think about again, this is from studying the Pfcas and Pfsas, those

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Jason Conder: Alkyl acids.

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Jason Conder: the head group on the acid is important to consider the carboxylates like Pfoa, pfna pfhxa, the ones that ended a those tend to accumulate more in the plants because they're more water soluble.

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Jason Conder: whereas the sulfonates things like Pfos, Pfds, pfhxs, things like that again, the ones that end in s those sulfonates tend to accumulate more in the animals. So you can kind of get some generalizations. You know.

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Jason Conder: The end story is, there's really kind of something to worry about. With all of this there's no good general rule and say, Well, if it's a carboxylate, it's just not going to accumulate very much. We can't necessarily say that it depends on what type of biota, what type of issue, you know, if you're in a terrestrial system or aquatic system.

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Jason Conder: So there's no easy answers basically is what I'm trying to say with bioaccumulation. So this just kind of puts it all together in one big slide. Again.

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Jason Conder: the long chain pfsas tend to bioaccumulate more in the animals, and the short chain carboxylates tend to bioaccumulate more in plants.

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Jason Conder: So moving on, how do we get ready for screening and baseline ecorisk for pfas. What are some of the logistical concerns that we're having right now, you know. One thing is, I say this to you know, new regulators.

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Jason Conder: my new clients, my colleagues in the consulting world. Just beware of science projects. Everybody is really excited. I get that. This is new and interesting chemistry. You have to really stick to our data quality objectives, regulatory driven risk, assessment, paradigm as much as you can.

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Jason Conder: Every data you collect out there needs to be related to answering that question about whether we're going to dig up the site or not. Remember, risk assessment is not ecotoxicology, science land. It is a decision-making process. We need to tell somebody at the end of the day we're to drive the yellow steel to dig a hole or not.

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Jason Conder: So again you got to keep track and make sure your investigations don't become bloated, and with all kinds of extra science projects.

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Jason Conder: you know, temper your own natural curiosity. Yes, there's uncertainty. We can manage it. But it doesn't mean we need to add a lot of extra science experiments to that.

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Jason Conder: So you know, one of the other big things I get. You know there's hundreds to thousands of pfas that we could be dealing with at these sites. It's just not possible for commercial analytical chemistry right now to capture all that. You know the full list for pfas for EPA. 1633 method. We can't even do eco risk for all of those 40 compounds

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Jason Conder: in general. What we're doing so far is focusing on those stable

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Jason Conder: sulfonates and carboxylates. Pfoa pfos. The ones we know about those are fairly toxic. They're fairly bioaccumulative. They're not going anywhere, not going anywhere because they're persistent.

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Jason Conder: And we can get some good Ecotox effects information on that.

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Jason Conder: It's a data gap. It's not perfect. There's guidance on how to, you know. Deal with that. People are thinking about that very intently.

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Jason Conder: you know. And the other thing is, the data gaps for vvas are being updated almost on a weekly or monthly basis. Again, there's new things coming out, Jason mentioned. Marine talks, data. I'll have a few more slides on that, you know. There's data gaps for sure. There's uncertainties again. That's eco risk assessment in general.

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Jason Conder: So you know, that's 1 thing to keep track of and make sure that folks doing the Ecorisk are up to date in the literature for pfas, the science, literature, the regulatory literature. These people need to be integrated with the updated landscape on pfas, and because it's moving quickly.

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Jason Conder: And a key point here is again unavoidable. But we can use the best information we have at the time to make the best available decision again. That's all we ask in a risk assessment.

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Jason Conder: None none of them are perfect.

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Jason Conder: So some just basic recommendations from my experience, working at sites. If you're out in the early stages of the process, get your risk, Assessor involved in planning the investigation again, Jason said, get them to the site. I can't stress that enough, but also have them involved in planning

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Jason Conder: site-specific investigations. How many samples you need. What do you need to measure things like that when and where, you know for terrestrial sites, if you're dealing with soil. Yes, you're measuring pfas and soil. Please also get organic carbon content of soil. That's not the be all end, all of predictor variables for pfas fate. But is it extremely helpful. Yes.

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Jason Conder: it can come in very handy. There are other things you can consider measuring as well that can help. But organic carbon is cheap, and it's a no brainer. You might consider some biota sampling at sites, you know, worms and insects and plants and things like that. We usually save that to later on in the baseline eco risk. Once we look at some soil data and try to figure out where things are and get a slera done.

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Jason Conder: we usually don't do groundwater or soil, gas or air for ecological risk assessment. Again, that's just related to the basics of where these animals are getting. Most of their exposure. Could groundwater emerge at a site and be a source? Yes, depends on your site. Depends on your animals again. Get your Eco risk, Assessor involved early and have them look at conditions in the conceptual site model.

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Jason Conder: You know, if you're dealing with aquatic system, there's lots of creeks and drainages, and there's always a nearby stream, or something like that that might be

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Jason Conder: at threat of a triple F pfas runoff. You definitely want to measure surface water pfas, sediment pfas again. You're measuring sediment. Get organic carbon, too, again. It's a cheap

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Jason Conder: thing to measure. It tells you quite a bit about fate of pfas. You might consider sediment poor water again. That's more of an advanced investigation. But things that we're working on now suggest it's a helpful data to have. If you're looking at doing some biota sampling. Yes, you can get benthic. Compilagic invertebrates are important. That base of the food web

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Jason Conder: plants, fish, other biota. Again, the biota sampling. It's always challenging the animals and plants never are where you want them to be. We usually save these for the later stages of the vera. In most cases.

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Jason Conder: Second big bullet there. Background sampling is huge. Consider background.

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Jason Conder: in a reference area, especially if you're nearby. Other sources say within 5 or 10 miles of

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Jason Conder: sources that you may suspect are pfas sources. You know. Cercla does not allow us to clean up below background. So that's something to very, you know, take into account. We need to understand background at these sites because many of our risk-based levels, as we get into new reference doses and cancerous low factors and things like that are pushing us towards cleanup

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Jason Conder: to background or close. So you need to know your site's contribution. And really, what's feasible, especially in large watersheds where you have multiple feefas sources your source, your site just may be one part of that, and that needs to be thought of and managed as a whole.

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Jason Conder: So number 3, I think a few questions on this early today. What about the pfas that might be there? But we can't really measure with 1633 or other sort of off the shelf methods. There's total organic fluorine method. There's top assay, there's piggy. There's things like that. We usually avoid

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Jason Conder: using these for risk assessments for eco risk. They don't have good, clear Dqos for thinking about effects and risk. They're potentially useful in a screening approach, or maybe some bounding exercises.

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Jason Conder: you know, I'm not going to say, never collect this sort of data, but consider it again. Avoid the science project, approach where you just throw everything in the kitchen, sink at your site. Think about again, good, clear, Dqos, but right now there's just no good way to shove these into a risk assessment and say, Well, yeah, everything is.

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Jason Conder: you know, we're going to do a top assay and assume everything's Pfos. You can't do that. There's no support for that

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Jason Conder: again. Think carefully through your Dqos here and and don't turn things into a science project.

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Jason Conder: Eco risk screening levels early on in your screening

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Jason Conder: process. You can use some screening levels. There's several out there.

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Jason Conder: These resources are available downloadable literature. The Argonne National Lab Grippo document, you know. Again, we're limited to a few pfas. There's soil, surface waters, sediment screening levels, things like that. There's a paper that we wrote in 2023 where we developed

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Jason Conder: some screening levels in water for amphibians. So there are screening levels out there again. Don't use them as cleanup levels. Do not panic. If your site is above these screening levels. They're generic. They're conservative. They're meant to indicate when you need to go further into the Vera process, as Jason indicated in his talk. But again, we have screening levels out there. It doesn't cover all 40 pfas and 1633, but it gets a few of the most important ones.

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Jason Conder: This is just another slide again, just showing some of the example screening levels. I will highlight that EPA just released the ambient water quality criteria for Pfoa and Pfos just last month, you know. Consider these in the screening level. There's for freshwater, you know, for example, for Pfos, it's around 250 nanograms per liter. You know. EPA also has some marine acute values for saltwater systems. These are.

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Jason Conder: you know, a little less technically supported. Right now, you know, we have some thoughts on that. Again, Jason and others. Us. Army corps of engineers and I are all working to get good talks, data so that we can develop good marine chronic values and get a little bit more support behind

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Jason Conder: criteria that we can use for aquatic life at sites. And again, also refer you to Jason's stuff that he has available by emailing him or the Navy folks on getting eco screening levels. We have an issue paper on that. That is part of the Navy emerging chemicals work group.

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Jason Conder: And again, emailed Jason, for that one.

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Jason Conder: Again, you know, Key Point, here is lots of screening levels out there different sources we're not working from from nothing. But again, use them wisely, and think about your receptors and get your ecorisk person in front of this

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Jason Conder: early on in the process

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Jason Conder: again, saltwater screening levels. That's been a big data gap for us, a lot of navy sites. There's not a lot of tox data out there on saltwater organisms. And when I say aquatic life, I'm talking about basically the food web plankton, algae worms and clams and bugs at the bottom of the ocean fish things like that. I'm not talking about higher level, vertebrate mammals and fish that may be involved, but just the

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Jason Conder: basic aquatic life, you know again, you know, EPA has some kind of took a stab at some of the basic ones. But again, we're working on.

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Jason Conder: you know, developing data that you know, Certip and Navy through the Nsd program has, you know, funded, you know, recognizing that there are these data gaps to get good quality data out there, so we can derive water quality criteria. There was a statement of need for this, you know, a few years ago, and you know, kind of in response to that, some of the work that I've been doing with colleagues at Us. Navy Naval Information Workers Center, Pacific and San Diego and CSIRO

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Jason Conder: in Australia. We're working on a 3 year lab Talks project looking at 10 target pfas, we're doing over 160 lab Tox tests with 10 different marine aquatic life species. A lot of good work here coming together. There's an additional project that's very similar to this one that's basically being led by David Moore, Us. Army corps of engineers that's looking at additional species additional pfas.

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Jason Conder: Both projects are going to have a lot of great data coming together, and will give us the data that we need to generate chronic aquatic life criteria for marine species. So that will be coming

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Jason Conder: soon. You know some of the initial observations that we've had from our work and David's work at the core. You know the marine aquatic life, for whatever reason they're just not as sensitive as freshwater critters. They tend to be a little bit more resilient to pfas. And

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Jason Conder: from what we're seeing so far, it's the invertebrates in the marine, much like in freshwater invertebrates, not fish tend to be pretty sensitive to pfas. Pfos is the most toxic that shouldn't surprise most people. The longer chain pfas tend to be more toxic.

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Jason Conder: The sulfonates, like Pfos and Pfds tend to be more toxic than the carboxylates like Pfoa, and from what we're seeing, so far, the kind of chronic thresholds are in the 0 point 1 to one milligram per liter range, and that's a lot higher than what we've really ever measured. At most of these sites.

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Jason Conder: you know, limited data at saltwater sites. There's a great review of a ton of great freshwater data, but we just don't see these sort of milligram per liter range concentrations in water at most of these sites. So the good news is that marine aquatic life. They're not that sensitive. They're not going to drive an eco risk, but they're going to hang around and bioaccumulate pfas. You remember a few slides back? I said. Bioaccumulation is key.

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Jason Conder: So you have fish invertebrates at some of these sites. Yes, they will bioaccumulate some of these pfas, and could be a risk to consumers like fishermen and birds and things like that at some of these sites, if there's the opportunity for these things to forage and catch fish and things like that. So something to be aware of

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Jason Conder: so getting into the kind of where the rubber meets the road. If you're getting into a barra and you're doing exposure and effects estimation, this is again the part of the process where your site is above screening levels, you're actually doing more of the nuts and bolts of an Eco risk assessment. You know

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Jason Conder: most of what we know about the toxicity and adverse effects of pfas when it comes to effects, characterization comes again from Pfoa and Pfos, and then a handful of their brothers and sisters in the carboxylates and sulfonates families

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Jason Conder: from what we see from animal studies, usually on rats, birds like quail

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Jason Conder: rabbits, things like that. We do see mortality and growth effects. If you dose them high enough, there can be reproductive effects.

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Jason Conder: There can be some organ specific effects, changes in the liver and kidney definitely immunotox endocrine system. Sorts of things. There can be tumors, of course, for plants. We usually see mortality and growth effects, so, you know. But those again occur really high concentrations. It takes a lot to do much to a plant. Usually what we're kind of revolving around in Ecoresk is effects on the mammals.

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Jason Conder: and as Jason alluded to and talked a lot about with Chris Custer's work, there's some great studies on pfas, you know, in field studies. And what we've seen so far is there's no clear smoking gun between pfas exposure and a real clear population level effect on reproduction growth mortality, you know. There's some suggestions, some associations, no clear smoking guns just yet.

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Jason Conder: There are a lot of people are looking at this. But again.

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Jason Conder: what we end up, you know, producing in the Eco risk is a prediction of potential eco risk in the field. So we need to do some good old fashioned ecology. Put the Eco back in the Eco risk and really test and see if these predicted effects are actually occurring. And so far it's not exactly clear. Our models are very conservative, and we tend to overpredict the effects.

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Jason Conder: You know mode of action. We talk a lot about that in toxicology, from what we're seeing. So far, you know, the data tend to say that aquatic life, you know.

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Jason Conder: worms and crabs and invertebrates and fish. It looks like it's our narcosis effect, much like a sort of a general organic chemical. It affects biological membranes. There's no clear key.

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Jason Conder: particular effect. There could be something interesting going on with insects because they tend to be a little bit more sensitive.

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Jason Conder: Mammals. For example, it's a general narcosis effect. Some maybe potential effects on fatty acids and other particular biochemical pathways again, not as important in terms of an ecorisk, you know, calculating hazard quotients, but it does play into how we deal with mixtures, and I'll talk about that in a minute, because all these sites you're not just dealing with Pfos and Pfoa.

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Jason Conder: you might be able to generate risks for the other compounds. And what do we do with that? In total? Do we add them up?

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Jason Conder: Do we look at them individually? That is a huge issue mode of toxic action is playing into that. And again, we're learning a lot about that right now.

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Jason Conder: So, getting in a little bit more detail, you know, at the base of the food web. You know, I mentioned this earlier, like, if you're looking at aquatic life fish and invertebrates most of the direct effects that we see occur at concentrations that are really high. You know, I mentioned for salt water. We're well into the milligram per liter range.

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Jason Conder: Most of our concerns about human drinking water and bioaccumulation in fish for other concerns for fishermen, risks

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Jason Conder: and wildlife risks occur at concentrations that are much lower than the effects that we observe on fish and invertebrates directly. So aquatic life aren't going to drive concerns. At most sites, it's going to be wildlife. It's going to be bioaccumulation issues.

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Jason Conder: plants and soil vertebrates, same song, second verse. It takes milligrams per kilogram concentrations to really do much to an earthworm or a plant.

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Jason Conder: And really we're going to be worried about bioaccumulation, to wildlife and other concerns at levels that are much lower than milligram per kilogram. So again, soil direct effects aren't going to drive risk assessments. It's going to be the wildlife issue. So you know, in tier one tier, 2 sorts of assessments, you know. Use those

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Jason Conder: soil measurements that we have water sediment, we can use the screening levels. But to address these sort of low traffic level concerns.

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Jason Conder: you know, we may hardly ever see an exceeds for these types of of levels. But again, we're going to be mostly worried about

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Jason Conder: birds and mammals. Bioaccumulation exposure, you know. Again, wildlife just tend to be the most sensitive, especially for Pfos, because it's bioaccumulative. It's fairly toxic, and most of the concern at sites at Af. You know, it's going to be driven by small animals.

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Jason Conder: You know the ones that hang around in small areas around the creek or the pond, or maybe a small patch of of terrestrial habitat. They have high site fidelity. They have high dietary exposures to eat, a lot of

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Jason Conder: insects and fish and things like that. Those tend to drive risk-based decisions for pfas, and really a lot of the other chemicals that we used to deal with at these sites

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Jason Conder: like metals and Pcbs and petroleum things like that. You can model exposures to carnivorous and wider ranging animals, like bald eagles

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Jason Conder: and panda and polar bears and great blue whales, but those are hardly ever going to visit your site, and most of the time yes, you can calculate exposure and look at risk. But it's not going to drive decision making. It's going to be the little shrew, the little duck things like that.

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Jason Conder: And again kind of echoing what I said earlier. The field studies people have looked at birds, looked at small mammals. In some cases they don't see a clear smoking gun that says, yes.

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Jason Conder: pfas is, you know, affecting this population of animals.

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Jason Conder: You know, there's some

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Jason Conder: thoughts about, you know, Custer and her data about maybe decreased hatching success and some tree swallows. But you know there's other chemicals involved. And again finding that good causal link between pfas and risk and effects is.

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Jason Conder: it's not quite been as black and white as you might think.

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Jason Conder: You know. There's other studies out there that really haven't seen much of an effect on a population level in birds, and you know, including

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Jason Conder: some populations with higher pfas exposures again, lots of work being done on this now, and I think it's worthy to do more work on it. Going forward.

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Jason Conder: Jason mentioned, you know, exposure factors in exposure estimation for wildlife. And you know I won't get

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Jason Conder: completely deep into this slide. But you know, typically what we do in in that

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Jason Conder: you know, screening level Bara sort of step here is, you know, we often have measurements of something in soil at a site. For example, you know we assume some conservative exposure modeling. And really, what we're trying to get to is over there on the right is how much in terms of nanogram pfas per day is a bird eating, or how much is a great blue heron, you know, or a

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Jason Conder: raccoon, or a coyote? What are they eating on a daily basis. Again, this is standard ecological risk assessment stuff. The problem is that we always need to know what's in their food. And again, for pfas, bioaccumulation is a real key thing, a lot of the exposure to these animals. It's coming from what they're eating and the pfas. It's bioaccumulating in the food web

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Jason Conder: and samples are often hard to come by. You can't necessarily just go out and snap your fingers and get fish and other things that easily. So we often start with abiotic data, that is, measurements in soil, sediment and water. And we predict those using a food web model in pfas. You know again, generally, what we end up doing is

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Jason Conder: taking those concentrations, feeding them into a food web model, organic carbon content for sediment. Soil is helpful. We have default, uptake factors. Again some work that we did in 2021 of our certip projects, we developed a modeling tool for this. There's some mechanistic models that are similar to Gobis models for the pathilic organics. Those have been used by Ecorisk folks for a long time recently out

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Jason Conder: paper by Kelly et Al. In 2024 this year just popped out. It's a really good paper. So these sorts of models can give us uptake factors that we can use soil sediment water to predict what's in the food web and then put that into our Eco risk model.

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Jason Conder: So we know what these birds and mammals are eating on a daily basis. And that's where we come up with our exposure estimates the model that we've developed. It's available out on the web. You can download it from that link there. These are intended for the ecological risk assessment professional. But it's a standard approach. And again, it's not like the Navy is mandating these spreadsheets. But please don't reinvent the wheel. There could be useful things in here.

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Jason Conder: These are completely modifiable. You have your own uptake factors from your own Trvs. That's great, too. You can pop them right in. But again, it's designed as a typical sort of model package that you would attach to a standard eco risk

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Jason Conder: that you would submit to a State or Federal regulator as part of an Eco risk assessment. And it's standard sort of stuff. The hard part was just pulling all the Pfas specific information into it. You know, we're looking at updating these models periodically, and they're out there on the web and feel free to download them, use them and contact me if you have questions on them.

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Jason Conder: So you know, when it comes to evaluating exposure. Once you have that, you know, estimate of how much your bird might be eating on a daily basis, or what your coyote might be ingesting in terms of how much pfoa on a daily basis. You need to understand benchmark exposure that might have caused an effect. And there are benchmarks out there. Most of it's based on mammalian and

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Jason Conder: a few avian studies in the laboratory where folks have dosed animals and looked at the effects. There are resources out there for these toxicity reference values tox benchmarks.

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Jason Conder: It's also called Sevs in Navy terms. There's again work that we did in 2020 to review a lot of this information and provide suggestions on what Trvs to use

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Jason Conder: Ripo's paper, has them. Narazano has Navy Tierravies something that Jason and I collaborated on with others from Jacobs is coming out with a trv document for Navy risk assessments for mammals and birds looking at Pfos pfhx. So please reach out to Jason on that for that white paper. Hope to get that out in peer review soon as well.

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Jason Conder: So there are good resources out there for effect, data for wildlife.

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Jason Conder: Okay? So.

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Jason Conder: going far and above into the advanced Eco risk assessments.

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Jason Conder: you know. Again, if you get to the end of your modeling step and you are predicting potential risks to your birds and your mammals. You can definitely put Eco back in the Eco Risk assessment. Go out and do some more data collection.

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Jason Conder: You can do things like toxicity testing passive sampling to understand chemistry better, looking at Bentha community assessment, to look at what sorts of critters you have at your site, you can measure pfas and biota to check those model predictions. Again, let's check those bioaccumulation models to make sure they're accurate. And again, this is sort of what we do for really any other chemical. We're not rewriting. The book here is

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Jason Conder: we're using our modeling tools to make predictions, you know, based on what those predictions say. Yes, let's go out and get some actual site data. If we need again, we can actually look at measuring Eco biological responses at some of these sites, you know, are the impacts that are being predicted by our models actually observable at the site and really thinking at it from a population and community level basis. Again, putting the Eco back in our process.

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Jason Conder: and again, not to make things too complicated. But again, focus on those Dqos. You know, we're not doing this just for science sake. We're trying to come up with additional add-on work if we need it. That helps us understand where and when and how to clean up a site. And and really, again, think about these research sorts of projects carefully and develop good Dqos can't stress that enough.

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Jason Conder: you know, getting to, you know, end and latter stages of the communication process, you know. Again, we come up with our hazard quotients. These are sort of standard approaches. I'm not going to reiterate that. But again, if your hazard quotient is above one, if your models predicting effects, or you know exposures that are above potential benchmarks that you're looking at.

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Jason Conder: it does not mean the end of the world. Look at your doses, look at your assumptions, your chemistry. Again. There might be things that you might refine in your assumptions, you might get more data. You need to communicate that with your stakeholders definitely talk about uncertainty. The fudge factor around some of these numbers as well is important to take into account again. It's just good open communication, good risk, assessment. And really.

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Jason Conder: you know, talk about what your model is predicting, and put that into a context as well.

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Jason Conder: So

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Jason Conder: uncertainties. You can't do an ecological risk assessment or a human health risk assessment without massive uncertainties. And

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Jason Conder: you know for pfas. One of the big things that always comes up is that there's mixtures. Yes.

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Jason Conder: there's more than just pfoa and Pfos at our sites. We may have multiple hazard quotients for multiple pfas. What do we? What do we end up doing for that? You know some of the recommendations and considerations you might

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Jason Conder: think about. Yes, acknowledge it as an uncertainty. That's an easy way out. But you might do some sensitivity analysis.

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Jason Conder: You may sum hazard quotients, hazard index. It's not completely supported by the literature. Again, we're thinking hard about what that mode of action is before you start summing hazard quotients of things. They need to be working on the same mode of action. From what we're seeing. So far, pfas looks to be working on a similar mode of action for most critters. So maybe this is where we end up heading in a few years. But there's some science that needs to be done before we codify this.

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Jason Conder: I would say right now it's more of a sensitivity step. Most of the sites I've worked at. When you do this it doesn't matter if you sum up everything. Or just look at Pfos.

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Jason Conder: Your decision on where to dig a hole is usually based on where the Pfos is located. But again, that's a hypothesis and something that I've been observing, and sure there's definite

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Jason Conder: exceptions to that rule.

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Jason Conder: secondly, you know what about those pfas that we detected a site. But we don't have Tox data, for we don't have a screening level. You know. We have pf, and a showing up in our soil, but we don't have a T or V for birds for that. What do we do for that? You know it's especially a challenge, you know. Again, for aquatic life for marine stuff birds I mentioned.

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Jason Conder: you know generally what we do is again, it's an uncertainty.

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Jason Conder: you might do some sensitivity analyses. You might look at similar chain links, you may qualitatively compare it to Pfos or other pfas with benchmarks. You may develop it against surrogate Trv. In some cases there are no good answers here. We're working very hard at really trying to unravel the best available approaches for that. And

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Jason Conder: sort of right now, that is a huge issue. We know about it. We're trying our best, and lots of smart people are thinking about how to deal with this in an eager risk.

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Jason Conder: 3 pfas, dark matter these are the unmeasured, unknown pfas that may be there, but we can't detect it. This is very analogous to what we deal with at a petroleum site. This comes up all the time. Most of the sites that I work with

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Jason Conder: you know, that are Pfat or their petroleum sites. We're often focusing a risk assessment on the 16 priority pollutant pahs.

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Jason Conder: And yes, there are hundreds to thousands of other petroleum hydrocarbons that may be present in

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Jason Conder: water sediment, fish, whatever we're looking at at these sites. But we often make these risk-based decisions

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Jason Conder: based on these indicator Ph

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Jason Conder: compounds, and assume by cleaning up for Benzoate Pyrene and a few of these other compounds that we're finding and can measure and understand, will

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Jason Conder: collect and capture risk associated with the rest of the potential mixture, that we may or may not be ever able to completely understand. Toxicologically.

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Jason Conder: that may be where we're headed with pfas. We may have a suite of indicator compounds.

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Jason Conder: We may come up with a

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Jason Conder: a way to look at some of carboxylates or something like that. It's a huge uncertainty. There's no good quantitative approach right now.

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Jason Conder: Try to resist those easy answers. You know folks have said, well, maybe we just measure a total pfas

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Jason Conder: somehow, and assume everything is as toxic as pfos. That is definitely not a good move

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Jason Conder: just beyond the carboxylates and sulfonates the chemical compounds, for these mixtures at sites are very strange looking. These compounds are not going to act all

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Jason Conder: the same way. So again, we need smart ways to think about this again. This is a recognized data gap and need. And we're working hard to try to figure out a good way to go about it. In the interim again. Most people, most sites I've worked at, we look at what we can measure and deal with, and assume that. Yes, if we clean up for Pfos, and the handful of compounds that we can understand, risk

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Jason Conder: will capture the rest of the

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Jason Conder: actual effects to ecological receptors. Again, an assumption definitely testable. We're working hard on on resolving those uncertainties.

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FRTR Presenter: Jason, I'm so sorry to interrupt. I think you've got about 30 seconds to wrap up if you can.

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Jason Conder: Great. Yeah, that's great. I'm coming at the end, you know. Quick site in Australia. We looked at for a triple F, not a Us. Navy site. Basically. What we ended up doing is, there was a pfas runoff issue to a beach.

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Jason Conder: This there was Pfos pfhx in the beach. Pore water, we said, Hey, yes, it's above local screening levels. These are Australian aquatic life screening levels. They were predicting effects to Benthic life and aquatic life.

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Jason Conder: You know there's lots of things we could have done modeling things like that, we said, Hey, let's go out and do the ecology. Let's do the biology. Let's see how the critters at the site

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Jason Conder: we did an intertidal survey. We looked at some really cool ecological metrics of the site compared to reference areas. The end result here is that the site itself, despite being well above the screening levels, was just fine. The ecology was performing just fine. There weren't any impacts.

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Jason Conder: We will close the site. We also did some modeling to look at wildlife and human health risks as well. But again, good story here is that sometimes you got to roll up your sleeves, and in this case put on your boots, wait out and do some muddy boots, biology, and look at what's going on test these models, test these conservative assumptions

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Jason Conder: and look at actual ecology, at these sites

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Jason Conder: conclusions. You know, we're we've we've learned a lot in the last 20 years a lot left to go. We can use

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Jason Conder: tools that we have

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Jason Conder: don't panic, lots of uncertainties, but we can work through this. We're never going to have a perfect understanding of pfas

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Jason Conder: never gonna happen, you know. Was this the too much science issue again? Focus on Dqos and getting toward that dig or not to dig

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Jason Conder: key question, communicate your uncertainties and what you're doing as an Eco risk assessor. Do right by the ecology. As Jason mentioned, some of these places have taken hundreds of thousands of years. Let's not rip them to pieces because of conservative modeling or fear of chemicals. Don't do anything stupid, and I think that's all I have. Eco risk is eco risk, whether it's pfas.

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Jason Conder: Many thanks for everybody for listening in Jason Spiker, my colleague, Jen Arblister Geosyntech, and others, and funding was provided by Navy Ritz, for which this presentation was developed. Thanks. A bunch.