1 00:00:00,380 --> 00:00:04,750 FRTR Presenter: Final speaker of the day before. We have sort of an open discussion of 2 00:00:04,900 --> 00:00:10,680 FRTR Presenter: what we have done today. And just a follow up is Dr. Natalie Karuna. 3 00:00:11,080 --> 00:00:18,109 FRTR Presenter: Usgs research ecologist, leader of the Tell me, I'm wrong. Molecular Toxicology laboratory. 4 00:00:18,280 --> 00:00:22,069 FRTR Presenter: All right in the Eastern Ecological Science center in Maryland 5 00:00:22,310 --> 00:00:31,500 FRTR Presenter: expertise in molecular toxicology, focusing on understanding, detecting, predicting the effects of environmental stressors on wildlife. 6 00:00:31,570 --> 00:00:33,230 FRTR Presenter: Hi, I'm doing okay. 7 00:00:33,440 --> 00:00:38,669 FRTR Presenter: All right. I better turn this over, it says, where you have some degrees. Biology. Phd. 8 00:00:38,770 --> 00:00:46,940 FRTR Presenter: Rensselaer, Polytechnic Institute, Ms. Toxicology University of Maryland, Bs. Biology, Colgate. 9 00:00:47,320 --> 00:00:48,190 FRTR Presenter: and 10 00:00:48,500 --> 00:00:50,909 FRTR Presenter: the floor is yours. Well, thank you. 11 00:00:52,570 --> 00:00:57,120 FRTR Presenter: Thank you very much. And I actually wanted to thank Jason and Jason for doing a great 12 00:00:57,230 --> 00:01:05,609 FRTR Presenter: set up for me. I'll probably be able to cut out a couple of slides because of you. So thank you. I'll say I'll take it. 13 00:01:05,610 --> 00:01:30,250 FRTR Presenter: But in contrast to Jason and Jason, I'm not a risk assessor. I don't even play one on TV. I am just not just well, I'm a toxicologist, so I don't. I. Most of my work is focused on studies to help support you guys the risk assessors. So that's kind of the work that I do. But my approach today to my talk, which I devised the title, I guess, after 14 00:01:30,360 --> 00:01:41,379 FRTR Presenter: the program was put together. But it is what it is. So my approach is strictly going to be from the point of view of a wildlife toxicologist. I'm going to give 15 00:01:41,430 --> 00:01:43,357 FRTR Presenter: a broad overview 16 00:01:44,270 --> 00:02:07,760 FRTR Presenter: of avian studies that are relevance to risk assessors identifying what we know already, and also what we don't know, and some of the challenges that we face as biologists. And then at the end, I'm going to tell you about a study that we're conducting right now under a cert up Grant, looking at pfas effects in a raptor species. 17 00:02:11,630 --> 00:02:19,919 FRTR Presenter: Okay, a quick review of definitions which many of these Jason and Jason have already covered, so I'm not going to spend too much time on them. 18 00:02:20,080 --> 00:02:44,959 FRTR Presenter: So when we're looking at exposure and effects that exclude diet. We're looking at the term bioconcentration, and that's how organisms absorb and retain substances, whether they be pfas or anything else from their surrounding medium in terrestrial organisms, which is what I'm primarily concerned with. That's from air through respiration. 19 00:02:45,775 --> 00:02:51,490 FRTR Presenter: And that's related obviously to bioaccumulation, which includes diet 20 00:02:51,700 --> 00:03:01,420 FRTR Presenter: biomagnification is the increase in contaminant over in a consumer over its diet and trophic magnification is 21 00:03:01,590 --> 00:03:07,000 FRTR Presenter: in a food web, the magnification that you see. So I won't spend too much time on this, since 22 00:03:07,160 --> 00:03:09,250 FRTR Presenter: this has kind of been covered already. 23 00:03:09,430 --> 00:03:16,509 FRTR Presenter: But I'll also be talking to you about the effects of pfas, and for regulatory or risk assessment purposes 24 00:03:16,530 --> 00:03:23,190 FRTR Presenter: really apical effects, such as survival growth and reproduction, are used, or of concern. 25 00:03:23,200 --> 00:03:39,989 FRTR Presenter: but effect endpoints at the biochemical, cellular and genetic level, also known as non-appical endpoints. They're still critical for understanding the mode of action of chemicals, and they're useful in a weight of evidence approach, even though they're not necessarily used for regulatory purposes. 26 00:03:44,490 --> 00:03:57,020 FRTR Presenter: Okay, in 2019, Ctac sponsored a workshop that focused on environmental risk assessment of pfas. And one of the papers that came out of that workshop which you see an image of here. 27 00:03:57,401 --> 00:04:03,910 FRTR Presenter: Provide a kind of a broad overview or review of existing data and identified gaps and research needs 28 00:04:04,678 --> 00:04:15,010 FRTR Presenter: that are that at that point were identified to enable comprehensive assessment of Pfasc Risk. 29 00:04:15,030 --> 00:04:20,309 FRTR Presenter: So I'm going to relate to what's in here and expand on this a little bit further. 30 00:04:21,490 --> 00:04:25,160 FRTR Presenter: so that paper identified several broad 31 00:04:25,340 --> 00:04:49,789 FRTR Presenter: needs relative to assessing ecological risks of pfas, and these included development of data that are specific to supportive supporting, predictive models, identification of species and endpoints that should be targeted for text, not texting, testing, sorry, and the need to develop screening levels in various matrices that can be used to predict toxicity. 32 00:04:49,930 --> 00:04:52,729 FRTR Presenter: and finally, identification of methods. 33 00:04:53,902 --> 00:05:09,169 FRTR Presenter: That are best suited for examining bioaccumulation and biomagnification of pfas. As I mentioned earlier. I hope, in my talk to provide an update on where we stand with regard to addressing these needs in avian species. 34 00:05:13,570 --> 00:05:14,290 FRTR Presenter: Yeah. 35 00:05:17,420 --> 00:05:34,229 FRTR Presenter: So I did a search recently in EPA's Ecotox database, just to see. You know I've read what I feel like a thousand papers on pfas toxicity, but I wanted to get a real sense of what the real numbers are. 36 00:05:35,084 --> 00:05:44,749 FRTR Presenter: And this is specific for avian research identified through that database approximately 74 references 37 00:05:44,840 --> 00:05:46,760 FRTR Presenter: related to 38 00:05:47,747 --> 00:05:51,810 FRTR Presenter: toxicity of pfas of all sorts in birds. 39 00:05:51,930 --> 00:06:14,510 FRTR Presenter: because the criteria that Ecotox database uses there are some studies that are obviously not included in this because they don't report, for example, detailed information on the species that were tested, or chemical information, or or they're focused only on chemical mixtures which may not be included in this particular database, but this still gives us a rough idea 40 00:06:14,510 --> 00:06:26,499 FRTR Presenter: of what is out there. These studies have looked at 11 different bird species. And of these 74 studies, 19 were in vitro 41 00:06:27,110 --> 00:06:35,447 FRTR Presenter: 55 were in vivo, and that included egg egg injection. So 30 egg injection studies out of that 55. So 42 00:06:36,050 --> 00:06:40,459 FRTR Presenter: just to give you kind of an idea of where we stand right now. 43 00:06:41,766 --> 00:06:44,450 FRTR Presenter: On these on avian studies. 44 00:06:47,708 --> 00:07:00,119 FRTR Presenter: So the 11 species that I identified through the Ecotax database range, from bald eagles to gulls, and to probably the most highly studied bird which is the chicken 45 00:07:01,094 --> 00:07:03,710 FRTR Presenter: although the vast majority 46 00:07:04,090 --> 00:07:05,750 FRTR Presenter: of the studies. 47 00:07:05,860 --> 00:07:23,600 FRTR Presenter: of course, were in galiform species, so 81% of all the studies were in galliforms and galiforms are chicken-like birds that are ground feeding birds, and these include quail and other similar types of species. 48 00:07:23,940 --> 00:07:38,519 FRTR Presenter: So there's really a lack of diversity in terms of the studied species. We have onesies and twosies of other species that are studied, but primarily most of the data that we have are from from chicken and and quail. 49 00:07:44,800 --> 00:07:54,290 FRTR Presenter: So the studies that were listed. These are all laboratory studies, of course, looked at both apical and non-apical endpoints. 50 00:07:54,829 --> 00:08:03,930 FRTR Presenter: Not surprisingly apical endpoints that are suitable for risk, assessment, such as survival or mortality, growth, reproduction, and development 51 00:08:03,960 --> 00:08:13,070 FRTR Presenter: have only been reported for chickens, Northern Bob, white quail, Japanese quail, and mallards, which is not surprising, because the majority of 52 00:08:13,430 --> 00:08:20,810 FRTR Presenter: studies of that sort, not just for pfas are are in those species because they're they're used very often as model species. 53 00:08:24,925 --> 00:08:32,630 FRTR Presenter: So. But despite the limited species and the limited number of pfas that have been examined in these studies. 54 00:08:32,850 --> 00:08:44,059 FRTR Presenter: acute studies or short-term studies have found that in general, as I think, Jason and Jason, both mentioned, sulfonates are more acutely toxic than carboxylates, and longer, longer chain pfas 55 00:08:44,100 --> 00:08:48,879 FRTR Presenter: are more toxic generally than shorter chain pfas. 56 00:08:49,130 --> 00:08:51,890 FRTR Presenter: These studies have also given us a glimpse 57 00:08:52,450 --> 00:08:55,800 FRTR Presenter: into differences in species, sensitivity to pfas 58 00:08:56,152 --> 00:09:12,790 FRTR Presenter: in the sense. If you look at mallards, for example, they show a little bit higher or Ld. 50 s. Than quail. So it's not very extensive database, but at least gives us a little bit of a sense that there is, or there are species, specific differences in sensitivity. 59 00:09:12,890 --> 00:09:26,180 FRTR Presenter: but with so few studies it's a little bit hard to generalize in terms of avian classes that may or avian groups that may be more sensitive than others. 60 00:09:27,840 --> 00:09:44,729 FRTR Presenter: There've also been chronic or longer term studies that have been conducted, and again, these show similarly the difference in sensitivity to sulfonates versus carboxylates, long chains versus short chain differences in toxicity. 61 00:09:45,656 --> 00:09:49,233 FRTR Presenter: And several studies that have 62 00:09:50,230 --> 00:10:16,260 FRTR Presenter: looked at mixtures with generally just one or 2 pfas, or 2 or 3 pfases together, and in some cases these mixtures have shown additivity. In other cases there's not additivity. So co-exposure is important in terms of influencing toxicity in such endpoints, such as hatching success of birds. 63 00:10:17,750 --> 00:10:25,999 FRTR Presenter: So basically depending on what mixture you have, you may see slightly different responses than you would if you looked at the individual chemicals alone. 64 00:10:26,590 --> 00:10:44,789 FRTR Presenter: There's also been exposure. So most of the studies have been exposure through feed. But there's also been exposure through drinking water, and that has also shown to be more toxic than food. So your sensitivities increased through exposures through water than through food. 65 00:10:50,650 --> 00:11:09,569 FRTR Presenter: So, although these studies, as I mentioned, are limited in scope and in terms of species, they have permitted the development of Trvs toxicity, reference values, and other effect benchmarks that are critical for risk assessment. But not only are these benchmarks critical for risk assessment, they're actually also very important 66 00:11:09,570 --> 00:11:20,700 FRTR Presenter: for designing future studies. Potentially in other species. They're giving us a baseline of values that we could use for setting dosing levels in studies. 67 00:11:26,925 --> 00:11:27,260 FRTR Presenter: Okay. 68 00:11:27,540 --> 00:11:42,129 FRTR Presenter: so. Interestingly, I think it's safe to say that the number of field studies outnumber avian lab studies for pfas within birds. Perhaps this is not surprising. Doing controlled studies 69 00:11:42,250 --> 00:11:53,229 FRTR Presenter: requires, you know, specific laboratory setups that may not be available in many in many research stations. 70 00:11:53,400 --> 00:12:19,769 FRTR Presenter: But so, while many of these field studies are limited somewhat in scope. Many of them just have examined, uptake, and possibly tissue distribution in birds. There are studies and more recent field studies in particular that have included both apical and non-appical effects, and their relationship to the various pfas that are being detected in the birds, and the mixtures that they may be exposed to. 71 00:12:20,230 --> 00:12:27,460 FRTR Presenter: and more and more. We're also seeing broader food web studies that are being conducted and published. 72 00:12:35,090 --> 00:12:35,850 FRTR Presenter: So 73 00:12:37,970 --> 00:12:47,017 FRTR Presenter: in addition to reporting important data on pfas concentrations as Jason. But actually, both Jason's mentioned 74 00:12:47,680 --> 00:13:11,919 FRTR Presenter: There have been studies that have looked at apical effects. They both mentioned Chris Custer's data and Chris Custer's studies, where in some cases she has found reproductive effects where others she hasn't. There's other studies as well, that have shown inconsistent results in terms of these apical endpoints in regard to pfas. 75 00:13:12,280 --> 00:13:13,070 FRTR Presenter: So 76 00:13:14,460 --> 00:13:24,870 FRTR Presenter: the most of these studies have been conducted on reproduction in the field in passerins there have, you know, for for logistical reasons, but also 77 00:13:24,870 --> 00:13:45,679 FRTR Presenter: Chris Custer, for example, has done her work over many, many years, using the same species. So that makes much more practical sense to continue that kind of data and getting good data out of those studies on reproduction. There are very many fewer, if not 78 00:13:45,960 --> 00:13:54,609 FRTR Presenter: none, that may look at really direct effects on on species such as raptors, but many fewer. 79 00:13:56,098 --> 00:14:10,849 FRTR Presenter: So let's see, what else can I tell you about these? The other effects that have been looked at, such as non-appical effects? There have been reports of. 80 00:14:10,880 --> 00:14:23,370 FRTR Presenter: for example, thyroid effects and other non-appical effects in birds from field studies. But the link to apical effects from these endpoints obviously have not have not been made. 81 00:14:24,370 --> 00:14:31,200 FRTR Presenter: and we need additional research to to make those make those connections between those different types of endpoints. 82 00:14:38,610 --> 00:14:41,480 FRTR Presenter: Okay, so what have we learned so far from 83 00:14:41,860 --> 00:14:44,004 FRTR Presenter: from these bird studies. 84 00:14:44,580 --> 00:14:55,020 FRTR Presenter: and not surprisingly, a lot of the results that we found in both field and laboratory studies with birds are not that different from what we see in other terrestrial organisms. 85 00:14:55,040 --> 00:15:04,700 FRTR Presenter: so, as mentioned before, pfas pfas are not generally lipophilic. They have a high affinity for for proteins and phospholipids. 86 00:15:05,613 --> 00:15:12,690 FRTR Presenter: In birds uptake is primarily dietary, but also somewhat through water. 87 00:15:13,990 --> 00:15:16,382 FRTR Presenter: birds also present another 88 00:15:17,280 --> 00:15:24,219 FRTR Presenter: interesting potential avenue for for uptake, and that's through preening when they 89 00:15:24,389 --> 00:15:40,359 FRTR Presenter: obviously use their beaks or mouths to to groom themselves in a sense, and so any kind of any pfas or other contaminants that have been deposited on their feathers also present the potential uptake route, but that hasn't been very well studied. 90 00:15:41,660 --> 00:15:51,409 FRTR Presenter: Respiratory uptake is mainly a route for neutral pfas, but this also has been actually very poorly explored in birds. 91 00:15:53,773 --> 00:16:01,100 FRTR Presenter: So elimination in birds occurs primarily via fecal deposition. 92 00:16:01,120 --> 00:16:06,740 FRTR Presenter: but also a very important factor for female birds is maternal deposition. 93 00:16:09,305 --> 00:16:10,415 FRTR Presenter: which is, 94 00:16:11,059 --> 00:16:34,039 FRTR Presenter: you know, basically in birds, essentially an annual event. So any uptake that the mother may accumulate over the year in between reproductive seasons. Then again goes another season of egg laying, then reduces some of her burdens annually. 95 00:16:48,209 --> 00:16:56,399 FRTR Presenter: So there! Recently, they've actually been quite a few or an increasing number of food web studies that have been conducted with birds. 96 00:16:57,192 --> 00:16:58,517 FRTR Presenter: Which is 97 00:16:59,400 --> 00:17:11,009 FRTR Presenter: imperative for understanding how pfas move through avian food webs. Some of the studies have shown similarity across the different species that have been looked at. 98 00:17:11,070 --> 00:17:14,560 FRTR Presenter: For example, biomagnification. 99 00:17:15,070 --> 00:17:26,749 FRTR Presenter: again, of long chain pfas, but not pfoa, is commonly reported. Short chain pfas is either don't bioaccumulate or bioaccumulate to a much lower extent. 100 00:17:29,700 --> 00:17:38,470 FRTR Presenter: But there are, however, differences that have been seen as a result of land use differences in the food webs that have been examined. 101 00:17:38,549 --> 00:17:54,899 FRTR Presenter: which means that the signatures that are of pfas that are seen in the birds, and and also then the movement through the food web is reflecting some of the signatures that are in the surrounding land use, or sources of pfas. 102 00:18:04,580 --> 00:18:09,909 FRTR Presenter: So there's been a recent or very recent publication. From this year. 103 00:18:11,131 --> 00:18:14,990 FRTR Presenter: That conducted a meta-analysis of pfas movement 104 00:18:15,000 --> 00:18:25,320 FRTR Presenter: via maternal transfer, and was trying to identify some of the sources of variation that you have in birds related to this. 105 00:18:25,820 --> 00:18:43,440 FRTR Presenter: So because controlled studies, of course, can't be conducted in all of the birds that have been sampled in the wild mining. This kind of existing data for commonalities across species is extremely important for understanding the risk of pfas in multiple species of interest. 106 00:18:44,560 --> 00:18:45,560 FRTR Presenter: Clearly. 107 00:18:46,050 --> 00:19:01,809 FRTR Presenter: as you can see in my second bullet. Mothers are extremely generous with their children, and they deposit a lot of pfas into the eggs, which is then, of course exposing their offspring and the embryo as growing in the egg. 108 00:19:01,950 --> 00:19:25,180 FRTR Presenter: According to the meta-analysis conducted in this publication in the birds that they examined, which are mostly seabirds. They have a 40% higher pfas level than the mother, and that's relative to depending on the particular study that they reviewed relative to either plasma levels or tissue levels that were investigated in the mother. 109 00:19:26,240 --> 00:19:37,189 FRTR Presenter: Again they reiterated that carbon chain, length and molecular weight are positively correlated with pfas transfer to eggs or to offspring 110 00:19:37,560 --> 00:19:46,939 FRTR Presenter: and larger clutch size, so clutch of each different species of birds obviously lay different numbers of eggs, and so, but the larger the clutch size 111 00:19:47,345 --> 00:19:55,614 FRTR Presenter: the greater the dilution, if you will, of what the mother transfers, and so the the generally. There's a decrease 112 00:19:56,666 --> 00:19:59,823 FRTR Presenter: pfas pfas transfer to the eggs. 113 00:20:02,860 --> 00:20:06,959 FRTR Presenter: because of the larger number of eggs that the mother may be laying 114 00:20:08,272 --> 00:20:27,949 FRTR Presenter: also, as mentioned before, pociferous birds, and those that have more opportunistic opportunistic diets tend to have a greater transfer rate than birds that feed primarily on insects. 115 00:20:29,450 --> 00:20:36,749 FRTR Presenter: Also, interestingly and not surprisingly, pfas. The this. This meta-analysis also confirmed that pfas and yolk 116 00:20:37,173 --> 00:20:43,886 FRTR Presenter: of an egg is greater than in in the albumin. This is has to do with 117 00:20:44,996 --> 00:20:53,329 FRTR Presenter: vldl levels in yolk, which vldl tends to bind as a protein. It tends to bind many pfas, so that's 118 00:20:54,920 --> 00:20:59,550 FRTR Presenter: where the majority of pfas are concentrated in in avian eggs. 119 00:21:00,150 --> 00:21:20,219 FRTR Presenter: Also, interestingly enough, the study identified that body weight of the bird and egg weight, and also the functional group that's on of the pfas don't affect transfer rates from the mother to the egg. 120 00:21:29,070 --> 00:21:33,158 FRTR Presenter: So with all these data, what are we still missing? 121 00:21:33,780 --> 00:21:35,500 FRTR Presenter: Well, as we all know, we have 122 00:21:35,570 --> 00:21:46,439 FRTR Presenter: thousands of pfas, very little time, and very little money, and very little existing data to to identify all the potential risks and and concerns that we may have with it. 123 00:21:46,510 --> 00:21:47,255 FRTR Presenter: But 124 00:21:48,840 --> 00:22:05,479 FRTR Presenter: We have, with the extensive data that we have for Pfos and Pfoa, but very little or no, in vivo effects data for the other pfas. As mentioned previously. This is a major unknown 125 00:22:05,490 --> 00:22:09,300 FRTR Presenter: when we're trying to assess the risk of of 126 00:22:09,420 --> 00:22:12,489 FRTR Presenter: pfas that are not either one of these compounds. 127 00:22:12,880 --> 00:22:19,970 FRTR Presenter: and that also creates effects, thresholds that are focused almost entirely on Pfos. 128 00:22:21,730 --> 00:22:27,219 FRTR Presenter: We also don't understand very well variability in tissue distribution, and 129 00:22:28,870 --> 00:22:57,340 FRTR Presenter: rates between different species, also in birds. Toxicity in general of any kind of chemicals, not just pfas is often different in precoctial versus altricial birds, so precoctial birds are like quail and chicken, which, of course, are the most studied. They develop almost to independence within the egg, and so when they hatch. They have already at least some semblance of feathers. They're pretty, self-sufficient. 130 00:22:57,340 --> 00:23:14,979 FRTR Presenter: sufficient, and they can eat essentially by themselves, and are not reliant on the parent. They also thermoregulate immediately after they hatch from the eggs altricial and semi altricial birds, which includes many passerins and raptors. 131 00:23:15,348 --> 00:23:28,229 FRTR Presenter: Are not self-sufficient. If you will, when they hatch. Many of them are born without feathers, as you see in the tree swallows up there, or they're born with very limited feathers, like the castroll 132 00:23:28,400 --> 00:23:43,639 FRTR Presenter: hatchling that you see below. And so their thyroid system and other biological pathways are not fully developed. That hatch, including their immune systems. And so their 133 00:23:43,940 --> 00:23:56,209 FRTR Presenter: have been shown differences with other chemicals between these 2 types of 2 groups of of birds. But for pfas we don't really know how that play, how that 134 00:23:57,860 --> 00:24:00,199 FRTR Presenter: plays a role in in toxicity. 135 00:24:00,860 --> 00:24:10,100 FRTR Presenter: Likewise has been shown in in other species as well, sex specific differences, of course, in elimination, again, relying or or related 136 00:24:10,840 --> 00:24:17,129 FRTR Presenter: primarily in birds to female deposition and elimination through egg laying 137 00:24:24,893 --> 00:24:30,316 FRTR Presenter: additional data gaps that we've identified. Also cross species boundaries. 138 00:24:31,320 --> 00:24:42,140 FRTR Presenter: the we we don't. You know, the integration between laboratory studies and field studies? Is getting better, but we still have a lot of. 139 00:24:42,400 --> 00:24:54,319 FRTR Presenter: I guess separation between the 2 in terms of being able to apply laboratory data with environmental studies because of the differences in species that are studied. 140 00:24:58,080 --> 00:24:59,070 FRTR Presenter: Let's 141 00:25:02,700 --> 00:25:29,959 FRTR Presenter: so there's a need to move in our laboratory studies from single pfas or or constructed mixtures to those that are actually reflecting what's in the environment, and important to look at actual adverse effects, at environmentally relevant concentrations which are not necessarily what are used to set lc. 50 s. Or Nox. They generally tend to use much higher levels than are actually found in the environment. 142 00:25:31,643 --> 00:25:37,276 FRTR Presenter: Other missing information that we have is how pfas interact with other contaminants. 143 00:25:38,210 --> 00:25:50,887 FRTR Presenter: you know, in most of our field locations. It's it's highly unusual for the for pfas to be the only stressor and these kind of interactions are actually poorly studied and and 144 00:25:51,747 --> 00:25:55,719 FRTR Presenter: in probably in all organisms, not just in in birds. 145 00:25:57,510 --> 00:26:02,399 FRTR Presenter: We also have limited data on uptake 146 00:26:02,770 --> 00:26:19,919 FRTR Presenter: distribution and excretion in non-model birds. And again, that has to do with again reflecting some of our lab studies being focused only on galliforms in general. 147 00:26:22,610 --> 00:26:32,990 FRTR Presenter: we also lack enough studies to look at chronic effects in birds, in controlled laboratory studies. 148 00:26:36,580 --> 00:26:39,828 FRTR Presenter: So what are our options? 149 00:26:40,670 --> 00:27:01,099 FRTR Presenter: these have also been identified back in the ankle paper. How do we approach this? How do we solve this issue with so many different pfas and the unrealistic challenge of testing all the species that we're interested in, along with all the many pfas. 150 00:27:01,200 --> 00:27:02,070 FRTR Presenter: So 151 00:27:04,040 --> 00:27:28,129 FRTR Presenter: There's been a move to try and incorporate new approach methods which are in vitro tests or short-term in vivo tests to try and identify some pathway specific effects that can then be used for modeling purposes, to try and identify sensitivities and differences in species. Sensitivity. 152 00:27:28,930 --> 00:27:30,730 FRTR Presenter: Other options include 153 00:27:31,870 --> 00:27:55,630 FRTR Presenter: focusing on pfas that are that are important in terms of production and and use. So if we're interested in a a triple F site. Obviously looking at patterns that are, or mixtures that are related to a triple F use are more appropriate than just you know, selection of of pfas. That may not be found in those sites 154 00:27:55,740 --> 00:28:05,290 FRTR Presenter: and prioritizing these pfas. For in vivo characterization based on structural classification, so using testing 155 00:28:05,470 --> 00:28:11,270 FRTR Presenter: again other than Pfcas and Pfsays to help reduce risk assessment uncertainties. 156 00:28:11,760 --> 00:28:20,680 FRTR Presenter: Finally, they recommended identifying a suite of model pfas or mixtures that represent ecologically relevant profiles. 157 00:28:21,855 --> 00:28:23,024 FRTR Presenter: So that 158 00:28:24,395 --> 00:28:36,900 FRTR Presenter: signatures that are found in different land use areas that can then be used specifically for toxicity testing and identifying which 159 00:28:37,290 --> 00:28:39,409 FRTR Presenter: mixtures should be used 160 00:28:40,720 --> 00:28:47,350 FRTR Presenter: so as an example. In 2020, Andrew East and his colleagues published a paper 161 00:28:47,760 --> 00:29:02,530 FRTR Presenter: which they addressed. This exact issue. The challenge of estimating potential risk to ecological receptors when we have so many different pfas that co-occur in any one given environmental sample. 162 00:29:02,730 --> 00:29:16,820 FRTR Presenter: So in their analysis, they characterized and prioritized pfas and pfas mixtures from a large data set of pfas measurements in surface waters and soils that are associated with air force installations 163 00:29:16,850 --> 00:29:19,300 FRTR Presenter: that used a triple Fs. 164 00:29:19,750 --> 00:29:40,030 FRTR Presenter: and these particular, the results of their study identified specific pfas that are highly present and patterns that are highly present and repeated at these multiple installations. And we're now using this kind of approach to identify, to study 165 00:29:40,560 --> 00:29:49,419 FRTR Presenter: or to run several animal studies, to produce data for risk assessment at installations that may have this kind of pattern. 166 00:29:50,110 --> 00:29:58,540 FRTR Presenter: So this is a study that my lab is involved in right now with the defense centers for public health. 167 00:29:58,580 --> 00:30:10,209 FRTR Presenter: in which we're looking at movement or simulating movement, trophic movement from mice to a raptor species, American castrum. 168 00:30:10,300 --> 00:30:27,449 FRTR Presenter: And we're looking at distribution, tissue distribution and body burden profiles of these pfas mixtures in mice, and then using that kind of that information to then expose raptors or the American kestrel. To these mixtures 169 00:30:27,670 --> 00:30:41,769 FRTR Presenter: the pfas mixture that the mice are being exposed to is again environmentally relevant, using the profiles that have been identified by Andrew 170 00:30:42,000 --> 00:30:43,869 FRTR Presenter: in the 2020 paper 171 00:30:43,960 --> 00:30:58,929 FRTR Presenter: and then using these along with Trvs that have been derived for pfas or pfos from controlled laboratory studies from other birds. And we're using these to identify dosing 172 00:30:59,527 --> 00:31:04,100 FRTR Presenter: the the doses that we've used for for this study. 173 00:31:10,510 --> 00:31:11,255 FRTR Presenter: So 174 00:31:12,310 --> 00:31:30,140 FRTR Presenter: the American kestrel which we're using in this study is a model raptor species that has been used for toxicity, testing for many years for various contaminants. It's a useful species, because it's amenable to reproducing in captivity. 175 00:31:31,163 --> 00:31:32,156 FRTR Presenter: The 176 00:31:33,260 --> 00:31:35,435 FRTR Presenter: it's it's use 177 00:31:36,480 --> 00:31:56,210 FRTR Presenter: it's been used for for studying anywhere from mercury to flame, retardant effects and pesticide effects. And so we've been able to fortunately use this as well for exposures to look at pfas effects. And in this study we're looking at 178 00:31:56,240 --> 00:32:02,879 FRTR Presenter: not only exposing adults, but looking at egg deposition from the adult pairs. 179 00:32:02,940 --> 00:32:14,489 FRTR Presenter: looking at apical endpoints and simulating trophic transfer, as I had mentioned, because they're being fed mice that have been 180 00:32:15,618 --> 00:32:21,581 FRTR Presenter: dosed with pfas profiles that have been identified like I mentioned by Andrews 181 00:32:22,270 --> 00:32:24,110 FRTR Presenter: publication. 182 00:32:25,810 --> 00:32:34,679 FRTR Presenter: So this schematic is showing our protocol. We had 20 pairs of American kestrels that were proven breeders. 183 00:32:34,850 --> 00:32:50,809 FRTR Presenter: They were divided into 4 doses, so the control plus 3 doses that one of the doses is below the Trvs that have been reported for Pfos. 184 00:32:50,870 --> 00:32:59,319 FRTR Presenter: One of the doses. The middle dose is basically at the Trv, and then one is 5 times the the Trv 185 00:33:01,110 --> 00:33:10,940 FRTR Presenter: in the what we've done is we've initially bled the birds prior to dosing. So we have a baseline information on their pfas profiles prior. 1 00:33:10.360 --> 00:33:19.919 FRTR Presenter: Then we bled the adults again. A month after dosing was initiated, which was just before their nest boxes were opened, and so, just before egg laying. 2 00:33:19.990 --> 00:33:38.019 FRTR Presenter: Once the eggs were laid, we sampled the 1st and the 5th egg of the clutch. Kestrels will conveniently continue laying eggs if you pull them. So we're looking at the worst case scenario, which is egg one, and theoretically the best case scenario, which is egg 5 3 00:33:39.510 --> 00:33:42.990 FRTR Presenter: and then allowing the the remaining eggs to hatch 4 00:33:43.620 --> 00:33:45.819 FRTR Presenter: the hatchlings are then 5 00:33:46.400 --> 00:34:04.603 FRTR Presenter: Were then received additional dosing because we switched the parents to a control diet in order to give us a little bit better control as to the dosing that the hatchlings were getting, and then, once the hatchlings fledged. 6 00:34:05.640 --> 00:34:18.029 FRTR Presenter: we were. We sampled both the hatchlings and the adults for tissue levels and plasma levels. And we're looking at multiple different endpoints. In addition to the apical endpoints of 7 00:34:18.230 --> 00:34:21.970 FRTR Presenter: of that were mentioned previously. 8 00:34:22.380 --> 00:34:34.649 FRTR Presenter: So this just gives us a list of some of the non apical endpoints that we're looking at. So we're looking at endocrine endpoints, immune clinical chemistry, testicular biomarkers. We're looking at basically a whole. 9 00:34:34.710 --> 00:34:40.870 FRTR Presenter: a slew of different non-apical endpoints in the both in the adults and in the hatchlings. 10 00:34:44.470 --> 00:35:02.760 FRTR Presenter: I have a couple more minutes left. So the data that we're going to get from from the Kestrel studies in terms of the endpoints that we use. We're also applying to a study that my lab is doing in wild raptors and other 11 00:35:04.235 --> 00:35:11.410 FRTR Presenter: apex avian predators. So we to look at how some of their 12 00:35:11.550 --> 00:35:24.150 FRTR Presenter: pfas levels may be related to the endpoints that we were looking at in the kestrels, looking to see if some of the data and and the responses that we see in the kestrels are also being seen then in wild bird species from across the Us. 13 00:35:25.900 --> 00:35:42.909 FRTR Presenter: and these are samples that are being collected by my collaborators from anywhere from the Chesapeake Bay, Cape Fear. We have some that are coming from Michigan from New England. So quite a diverse sample set that we're going to be that we've received and we're receiving. 14 00:35:44.300 --> 00:35:57.589 FRTR Presenter: Okay, I have 1 min left, so I will end there. I think I'm on time. I wanted to thank the Usgs Environmental Health Program, but also cert up for the funding that they provide. And I'll answer any questions. 15 00:35:57.700 --> 00:35:58.740 FRTR Presenter: Alright. 16 00:36:04.380 --> 00:36:09.439 FRTR Presenter: Now, if there are questions in the room I'll start there. So I'm going to let Linda go first.st 17 00:36:11.223 --> 00:36:23.249 FRTR Presenter: I was curious to know, because I've been. I've read just a few papers about the amount of pfas found in the eggs, and I'm kind of thinking like Ddt. Like how many generations before 18 00:36:23.300 --> 00:36:30.449 FRTR Presenter: it really became apparent. And I was just curious. Your thought, I I know there's probably it doesn't sound like there's any data, but 19 00:36:30.800 --> 00:36:34.829 FRTR Presenter: I mean, have enough generational studies been done to know 20 00:36:35.020 --> 00:36:42.030 FRTR Presenter: how it do we know anything? No, it's it's funny you said that because one of the things I was thinking of when we were doing the Kestrel study. 21 00:36:42.060 --> 00:36:59.789 FRTR Presenter: You know I have limited number of birds, but wouldn't it be great to dose them in one year, and then let them go, and then they'll reproduce again right? And they can. You know, we could take them out X number of years and see how long the deposition continues right. How long? What's retained in the mother continues to be deposited? We haven't done that. 22 00:36:59.790 --> 00:37:22.540 FRTR Presenter: but I mean we had so many options and so many unanswered questions right? But I don't know of any. You know. Real multiple generation studies, I mean, I think in, I guess in quail. They've done kind of sort of what we did right. It's sort of to the next generation, but in terms of further out than that I don't know of any. I don't know if anybody else does. But. 23 00:37:24.910 --> 00:37:25.850 FRTR Presenter: Jason. 24 00:37:27.269 --> 00:37:33.900 FRTR Presenter: Natalie, I just wanted to ask your Pfhx. A dosing concentration is that based off 25 00:37:34.270 --> 00:37:37.249 FRTR Presenter: the water concentrations from Dennis at all? 26 00:37:37.320 --> 00:37:48.500 FRTR Presenter: No. So the that was basic again. So the the profile that Andrew East came up with from some of their studies. It's the Rel. It's relative to the amount of Pfos 27 00:37:48.580 --> 00:37:55.339 FRTR Presenter: right? So what they found in terms of their profiles and what came out of the mouse injection studies is how we determine. 28 00:37:55.530 --> 00:38:01.529 FRTR Presenter: You know the relative concentration to Pfos in the mixture. Okay, thank you. 29 00:38:04.090 --> 00:38:06.689 FRTR Presenter: All right. Anybody else in the room? 30 00:38:09.760 --> 00:38:19.270 FRTR Presenter: Alright. I see some messages are coming in, but kent per the agenda. This is our open panel conversation. Right? 31 00:38:19.920 --> 00:38:22.649 FRTR Presenter: Why not? Why not open the floor? 32 00:38:25.760 --> 00:38:26.630 FRTR Presenter: Well. 33 00:38:28.510 --> 00:38:30.109 FRTR Presenter: you're gonna switch gears. 34 00:38:31.210 --> 00:38:33.240 FRTR Presenter: It's if you'd like to go. 35 00:38:33.780 --> 00:38:37.479 FRTR Presenter: I say, what? What do we say? Roundtable with our presenters? 36 00:38:45.400 --> 00:38:46.090 FRTR Presenter: Hmm.