Hello and welcome everyone. My name is Dane Menke. I am the digital marketing manager here at Regenesis and Land Science.

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Today’s presentation will discuss notable PFAS regulatory actions in 2023 and provide an update on the state of the scientific research that is driving these regulations. With that, I’d like to introduce our presenter for today. We’re pleased to have with us Taryn McKnight, PFAS practice leader for Eurofin’s environment testing. Taryn McKnight has over 20 years of experience in the environmental testing industry. As one of the company’s subject matter experts on PFAS, she contributes to multiple organization and agency work groups to address PFAS challenges, including her current role as co-chair of the NGWA subcommittee to develop a white paper on PFAS forensics. With her expertise, she provides technical guidance to clients in setting up programs to achieve their site-specific objectives, and to agencies with understanding their analytical options and data usability considerations.

All right, so that concludes our introduction, and now I will hand things over to Taryn McKnight to get us started.

OK, great. Thank you so much, and thank you for the invitation to speak to you all today. So we are going to cover the State of the Union from a regulatory perspective. And I thought as we kind of come to the end of the year here, we could start off by setting the stage with some of the trends that we’ve seen have emerged as of late. So we all know PFAS is really exploding in the US. There’s a tremendous amount of funding being directed towards the investigation and the remediation of PFAS contaminated sites. certainly everybody expects the number of presumptive or confirmed sites to continue to grow. Although we’re gonna talk all about what federal regulations are underway today, I do want to remind everyone that from a federal regulatory standpoint, we’re still operating in a realm mostly devoid of regulatory drivers. Although there have been some developments under things like Tosca, we have any regs driving cleanup or compliance on the environmental side as of just yet. And I don’t know about you all but it’s hard to imagine being much busier than we are now isn’t it?

I think this is really just the tip of the iceberg though so buckle your seatbelts. And with that PFAS is spanning now far beyond the traditional environmental work that most of us support. We’re agriculture, and biomonitoring. And these are some of the prevailing trends that we see right now. So I think these are largely being driven by legislation, litigation, and also some social justice efforts. So until some of those emerging treatment technologies are really vetted on a full scale level, the cost of remediation still remains quite high. There is a dramatic trend towards treating PFAS as a class, and I’m gonna talk more about that today.

With the latest interim health advisory limits, there’s this suggestion that there’s really no safe level, at least for certain PFAS. And with the plethora of lawsuits, and of course that looming hazardous substance designation, there’s this feeling that anyone who’s ever come in contact with PFAS may potentially be liable. So some pretty hefty trends for us to grapple with. And I think from those trends, one of the more significant challenges that we’re facing is this growing debate within the scientific and regulatory communities about the mere definition of a PFAS, especially if we’re gonna treat PFAS as a class. It’s really critical to know what it is we’re trying to clean up or comply with. And of course, risk assessors are gonna have heck of a task in front of them.

So for a little context here, about 10 years ago we used a working definition that would included about 200 compounds. So now in 2023 we have a variety of different definitions we’re working with. Within the US EPA alone there’s multiple different definitions.Each of those kind of range in the thousands, just over 10 ,000 compounds. But if one used the recent definition from OECD, this would include over 6 million substances. So quite the range we’re talking about. And of course all of this debate over this broadening definition of PFAS is transpiring against the backdrop of these ever-decreasing human health risk levels for individual compounds.

Okay, so now let’s dive into those regulatory updates. The National Defense Authorization Act or NDAA has really become a preferred tool for passing PFAS legislation and this year was no different and whether you the work that you do falls under the DOD’s program or not, Congress manages to pass several provisions each year that are well outside what you would think of as being a scope of DOD in this bill. So there’s two in particular that I wanted to highlight here for you. First was this requirement for the DOD to follow the strictest of the following standards for response action. So a state standard, a federal standard, or a health advisory. Of course, a few states do have state standards and they all vary a little bit, but we don’t have a federal drinking water standard yet. I was personally very curious to see how the health advisory piece of this would be handled, but it appears that that interim status for PFOA and PFOS may be a loophole because in a DOD memo from July of this year, The DOD confirmed it is still using the 70 part per trillion advisory limit until such time that a federal standard is promulgated. Then there was this unusual Clean Water Act requirement, essentially directing the EPA to address PFAS under the Clean Water Act with prescriptive requirements. And I’ll tell you more about those when we get to the topic of wastewater.

So speaking of the DOD, they are required to report to Congress each year on the status their investigative and cleanup efforts specific to PFAS. And so this last report was compiled in September of this year and this is a snapshot from that report. So the DOD states that they’ve completed those preliminary assessments or site investigations at 425 of their DOD installations or National Guard facilities and then they’ve initiated remedial investigations at 275 of them. those 275, there are 245 that are estimated to be in the proximity of groundwater aquifers that serve as the primary or secondary source of drinking water. So as you can imagine, they are very focused right now on that pending drinking water rule. DoD is also continuing their research efforts under CERTA-BSTCP. They’ve got about a hundred projects related to PFAS, either treatment, sampling, analysis, or monitoring. And as I mentioned, there was that memo published in July, which also directed facilities to prioritize implementation of interim actions under CERCLA as expeditiously as possible.

The DOE, Department of Energy, also kind of more recently joined this field. They published their own PFAS strategic roadmap. That was last August and by October, had already published an initial assessment PFAS at their sites. By December, they published their PFAS research plan, which is also meant to leverage kind of the unique facilities and expertise that they have within their national laboratories. And then they also published a sampling guidance plan, and they’ve got a disposal guidance plan on the docket for early next year, so quite the flurry of activity from DOE in just a short 12-month span. Other developments that came out of congressional mandates include a new mill spec for flooring free foams. This was published in January of this year. This specification is intended for delivery systems and equipment for extinguishing land-based liquid fuel fires. So we’re not going to see this on you know any of our aircraft carriers yet.

The requirements include using a lab that is DOD accredited specifically for a triple F by draft method 1633. The challenge here is that draft method 1633 was not written or validated for HFF products. Also, the sum of discrete PFAS may not exceed one part per billion, which would also be very challenging to achieve in this matrix using the prescribed method. As a follow-up to this action, NAVSEA added the first flooring-free foams to the qualified products list. That was just in September, however, it looks like the defense secretary is expected to invoke some statutory waivers that are gonna give them as much as two years to comply with this congressional mandate, which is supposed to go into effect October 1st of next year, which would bar the use of any PFAS-containing foams. So they’re expected to call upon those waivers because they’re starting to realize the length of time it’s gonna take to transition all the equipment the new foams and they’re also still struggling to find suitable foam replacements for all their applications.

The Federal Aviation Administration or the FAA has also notified airports that they may begin using these flooring free foams that meet the new mail spec although airports are not required to use the new foams so that’s an important distinction. In response to the fact that 1633 was not developed for this purpose. There is an effort underway under startup BSTCP to create a method that could be used as the standard method to measure total PFAS in fluorine-free foams at that one part per billion limit. But in the meantime, you’re likely gonna have to depend upon a user-defined technique developed by the individual laboratory to achieve these objectives.

Okay, so continuing on with obligations under the NDAA, although this time, this is all the way back the 2020 NDAA, the EPA proposed reporting and record-keeping requirements for PFAS under TOSCA. Now this was all the way back in June of 2021. So after a long delay, which was largely due to the need to convene a small business advocacy review group, as of September of this year the rule has been finalized. So what this means is those who have manufactured or imported PFAS in any since January of 2011 must report information regarding a lot of stuff. Uses, production volumes by category of use, byproducts, environmental and health effects, worker exposure, and disposal. And the new rule notably extends PFAS reporting to the manufacturers not only of PFAS but also of articles that use PFAS in their manufacturing process. And there are no de minimis exemptions, so PFAS in any amount has to be reported on.

According to the agency, they expect that this rule will provide the EPA with pretty comprehensive data on more than 1 ,300 PFAS compounds. In a similar vein, EPA has updated the Toxics Release Inventory Rule, or the TRI, to address PFAS reporting obligations as well. So facilities across industry sectors have to report each year how much of each chemical is released to the environment. Right now, there’s 189 PFAS with a threshold of 100 pounds per year that are currently subject to this rule. The new rule that they just passed classifies PFAS as chemicals of special concern. And what that does is removes this long-standing exemption that allowed facilities to basically avoid reporting PFAS chemicals that were used in minimal concentrations. So, companies can no longer use this de minimis exemption to disregard chemicals with concentrations below 1% in mixtures or products.

In addition to that, the de minimis exemption for supplier notification requirements has also been eliminated, which means suppliers can no longer exclude notifications to purchasers about mixtures or trade name products with PFAS, even if they make up less than 1% of the mixtures. Speaking of that last world I just told you about, I bet those purchasers sure wish that this was an effect before they had to do all that reporting. I know that everybody is really worried about how they’re even going to know what products they use have PFAS in them because you have a lot of this confidential business information stuff going on. So EPA reasoned that the elimination of this exemption was necessary in light of the surprisingly low number of PFAS-related submissions that were made for the 2021 and 2022 reporting years. So on that note, this rule goes into effect for next year. We’re going to have to wait until July of 2025 to see those results because that’s when reports are due for the 2024 reporting year.

And then lastly, interestingly enough, the final rule preserves the TRI article exemption. So, this does limit compliance obligations for manufacturers of parts and finished products. And that’s in contrast to the TOSCA reporting rule I just mentioned, which did not include an article exemption. EPA TOSCA also manages the National PFAS Testing Strategy, where they basically develop these categories of PFAS, and they’ve based it off of information about similarities in structure or chemical properties, existing test data because everybody keeps talking about this world of PFAS is you know potentially thousands maybe millions of compounds and how are we ever going to develop toxicity information for all of them. So this is an effort to boil this down to something a little more manageable. So right now the agency is looking to obtain critical information on more than 2 ,000 similar PFAS that would fall within these categories.

This A snapshot here shows you the chemicals they’ve identified. They were only able to find manufacturers to whom they could issue test orders for 24 compounds. So that was kind of a limiting factor. So far they’ve issued three test orders, two at the beginning of this year and one just in this last August. Two of the three are GenX related, HFPO and HFPO-DAF. And so the companies that are in receipt of these test orders right now required to conduct a series of different tests. The first block of results are due 446 days after the order takes effect, and then that data is going to inform decisions about what additional tests are necessary. So this is definitely not an instant gratification sort of endeavor, but is expected to provide, you know, a plethora of information at the end.

Okay, moving along to wastewater now. On January of this year, the EPA released their final effluent guidelines program plan 15. In it, the EPA stated it would not pursue further action for various categories, but that it would continue to monitor those categories moving forward. However, remember that 2023 NDAA I mentioned earlier that included a stipulation about the Clean Water Act? Well, here it is. It basically says the EPA will publish affluent limitation guidelines for all the different categories it has mentioned in the plan and on their specific timelines, like June, 2024 for the plastics and chemicals, electroplating and metal finishing categories, June of 2025 for textile mills, electronic components and landfills. So you can see the comparison there in blue was the EPA’s original plan and in green is what the NDAA has stipulated. So that’s a pretty interesting turn of events. And I’m not sure if the Program Plan 15 has to get updated to reflect these mandates from Congress or what the next steps are exactly, but I haven’t seen any other movement on this since the first of this year when both of these documents were first published.

So in Program Plan 15, EPA also announced its intent to initiate a publicly owned treatment works or POTW influence study of PFAS. And that effort appears to be underway. So EPA is in the midst of developing an information collection request, they call it an ICR, to gather data on the amounts and types of PFAS that are entering wastewater treatment plants. And so this is to determine which industrial sectors may need those technology-based effluent limits developed for them. So EPA, I believe, is hoping to submit their plan to OMB for review before the end of the year with the goal of collecting these data from 2024 to 2025. And I also think it’s interesting to note that this sampling would include the 40 compounds from 1633 as well as absorbable organic fluorine from 1621. So that’s that total PFAS proxy measurement.

In addition to the Program Plan 15, the EPA also issued a guidance to the states in a memo. This was at the end of last year. And although it’s not binding, this more recent guidance document provides recommendations to the state’s agencies that have NPD’s permitting authority on how to address PFAS in those permits. Specifically, the guidance recommended that the permits require quarterly monitoring for 40 PFAS using the Draft Method 1633. and they did at that time mention the availability of the draft 1621 method for the analysis of absorbable organic fluorine but they said if appropriate. PFAS monitoring has already been incorporated into certain industrial discharge permits in states like Massachusetts and Colorado but we have yet to see really widespread adoption and it seems that there is some in doing so. So to assist the states with taking these actions, the EPA recently updated their website to provide additional resources. That includes example permits, which was a request from the states, example discharge limits, FAQs, training materials, things like that, and they also created a new best management practices fact sheet.

All right, moving on to drinking water now. So I’m going to spend a little bit of time talking about UCMR. The process for establishing drinking water standards for PFOA and PFOS began many, many years ago under the UCMR 3, which is the unregulated contaminant monitoring rule. And in an interesting turn of events, we started this process all over again with the current round, UCMR 5, which is underway as we speak. So is going to occur from 2023 to 2025. And there’s a number of really interesting points to note about this. So the first time in UCMR history, they’re going to be looking at the same chemicals twice. And due to a more recent change in the Safe Drinking Water Act, this monitoring will now affect more public water systems. So as opposed to the previous 10 ,000 customer threshold, it’ll now include systems that include more than 3 ,300 customers, and the reporting limits for PFAS are much lower this time. And then the EPA required the utilization of two analytical methods to capture the full target list of PFAS compounds proposed. That’s methods 533 and 537.1.

So as of October, EPA has released some preliminary results from UCMR-5, and here’s some highlights for you. PFOA and PFOS were measured above the health advisory levels in about 10% of public water systems. One public water system out of the 3 ,000 that have tested so far measured HFPODA, that’s the GenX chemical above the health advisory. PFBS, which also has a health advisory, has not yet been detected in any of the systems and of the remaining 25 compounds 14 were measured at or above their minimum reporting levels by at least one public water system and no public water systems have reported results for the final 11 PFAS. I think so far these results represent Something like 20% of all results that will be reported by the end of 2025. And then if you’ve been following the latest news, DuPont, Chemours, Corteva, and 3M have settled with public water systems across America where essentially any provider with a measurable result for any of these 29 PFAS will be considered part of that class. So it’s really interesting that we’re seeing those litigation data and these monitoring data all kind of come together at the same time.

Now in contrast to those updates, there are many more PFAS available for analysis beyond the 29 compounds that are included in UCMR-5. And so with that in mind, NRDC initiated a nationwide study to assess the drinking water of specifically impacted communities. And they found detections for an additional 12 PFAS that are not captured by either of the existing drinking water methods and therefore the UCMR-5. And I think, unfortunately, it’s just these regulatory statutes are struggling to keep up with the rapid advancements that are being made in the PFAS space. So for context, it took the agency 10 years to go from monitoring for six PFAS in drinking water to 29 PFAS in drinking water. But the technology for doing that much and much more had existed many years ago. Then when you look at how lengthy the process is for the EPA to regulate chemicals in drinking water or how long it takes to develop and validate methods to test for these chemicals, it’s really hard to imagine how they’re going to keep up with the pace at which the concern over PFAS is increasing and certainly with the pressure from the legislatures is mounting.

Okay so on that note let’s take a look at where drinking water standards really begin. The US EPA published the fifth contaminants candidate list late last year where we see something new regarding PFAS. So the way the CCL works is proposals for contaminants for consideration are submitted usually by the scientific community and then in accordance with the Safe Drinking Water Act the EPA will publish this contaminant candidate list every five years. Often the contaminants that are selected for monitoring and drinking water under the UCMR will come from this list. Then if the EPA makes a determination to regulate a contaminant, the agency has to initiate that process to propose the National Primary Drinking Water Regulation like they have just done for PFOA and PFAS. And what’s remarkable about the current CCL-5 is that it lists PFAS as a class of chemicals. So this was really the first time we saw the agency lay the policy foundation for treating PFAS as a class.

And of course, again, the importance of the definition of what constitutes a PFAS presents itself here. I’ve included the definition EPA used for this particular listing on the slide, which doesn’t actually match other definitions that they’re using in other places. But anyways, this means that the next time they select contaminants for monitoring under perhaps UCMR 6, it is possible they could select PFAS as a class rather than trying to play catch up with adding whatever compounds they’ve expanded their drinking water methods to capture. Okay, so now looking at the other end of that process, we have the end result or almost end result, which is the proposal of a national primary drinking water regulation, in this case for PFOA and PFAS. The final rule was originally listed for final adoption in September of 2024, but in the EPA’s latest update to their unified agenda, which came out this fall, they’ve listed it for January of 2024. And that’s after receiving 120 ,000 public comments. Even with that, officials continue to state that the final rule will be out before the end of the year. That may be a little ambitious because I think as of just before Thanksgiving OMB had still yet to begin review of the final rule, but in any case it’s certainly just around the corner.

This rule has a pretty straightforward limit for four parts per trillion listed for PFOA and PFAS, but it also a hazard index approach for a handful of other compounds, so let’s take a closer look at that. For those that are wondering about the hazard index approach and what that means in terms of potential for exceedances, here’s the basis for that calculation. So it really all depends on how low the health advisories are and what concentrations are present for all of those compounds. And remember, the health advisories are based off of the toxicology, not necessarily what’s technically feasible. So it doesn’t have those constraints, let’s say. For example, EPA just released its tox assessment for PFDA. This is a long chain perfluorinated chemical, longer than PFOA and PFOS, so no surprise that the reference dose is similarly extremely low. Although EPA has to publish a health advisory for this compound. If they do, it could be in the very low part per trillion or sub part per trillion range like we saw with the interim house. So if this were added to the hazard index, it would have a significant impact on exceeding this threshold.

So just to put this into context for you, looking at the limits we have here, if any two of let’s say GenX, PFNA and PFHXS are detected at five parts per trillion or higher, the hazard index would be exceeded. So five parts per trillion is a pretty trace level, folks. Okay, so most of our regulatory efforts to establish limits for PFAS include not only occurrence data like what we saw from the UCMR, but also toxicity data. So EPA uses these RSLs to determine whether removal action or further investigation is needed. So the creation of RSLs for PFAS compounds provides a nice clear path for the evaluation of certain PFAS as part of site cleanup actions. And so to that end, the EPA continues to chip away at toxicity assessments for individual PFAS. We’ve recently established health advisory limits for PFBS and HFPODA. These were both replacement chemicals for longer chain counterparts, PFOA and PFOS. The assessment of the PFAS that are listed here are in various stages, but we do have final reference doses or draft reference doses for some of them. And as you can see, we’re hoping to get some of these through the final part of the process by early next year.

Okay. And then we have everyone’s favorite heavy hitters, CERCLA and RCRA. Conversely, the timeline for finalizing the rule designating PFOA and PFOS as hazardous substances has slipped from August of this year to February of next year. And of course, under CERCLA, even closed sites can be reopened and has been remarked by agency officials just as of last month that the EPA likely will do so on a case-by-case basis. The EPA has already identified nearly 200 Superfund sites where PFAS are present and is applying its risk assessment guidance to those chemicals. Another update from the EPA’s unified agenda, they provided an official date with a notice of proposed rulemaking expected in August of this year to designate PFOA, PFOS, PFBS, and HFPODA as hazardous constituents under RCRA, but they have since missed that date. Those chemicals listed would be subject to corrective action at hazardous waste treatment, storage, or disposal facilities. And once they’re listed as RCRA hazardous waste, the waste is also considered a hazardous substance under CERCLA. So I guess we have to wait and see which one transpires first.

And if these were to be listed as hazardous air pollutants, which there is some evaluation going on about that right now, that would also automatically list them as hazardous substances under CERCLA. So lots of pathways here to these designations that have really far-reaching implications on cleanup and liability, and we will just have to see which one transpires first. And then EPA is also racing to meet a congressional deadline for publishing an update to their PFAS destruction and disposal guidance. It is expected by the end of the year as well. They’ve stated that the finalized guidance will address analytical tools for demonstrating this successful mineralization of PFAS that’s occurring and maybe some guidance on how these tools could be used for that. And then one area where there seems to be, well, for a long time, there seemed to be a little bit of a disconnect between the state and federal priorities was on biosolids.

The PFAS roadmap has the following listed. It says the EPA expects to complete a risk assessment of PFAS and biosolids by the winter of 2024 to determine if regulations are needed, and this would only apply to PFO and PFOS. And we all know states have been struggling for years with whether to restrict land applications of biosolids, what limits are appropriate to use, and if biosolids are in fact, you know, posing a risk. So the EPA’s Water Office Chief, the Environmental Council of the States and the National Association of State Departments of Agriculture have all partnered up together to tackle this issue. And in October, the EPA administrator pledged to work with these groups to preserve the management methods, that being land application, incineration, and landfilling, of course, while protecting human health. And the EPA estimates that in 2021, large facilities land applied 43% of their biosolids. They landfilled 42% and incinerated 14%.

Okay, lastly, moving outside the environmental realm a little bit, we have all the consumer product legislation that’s going on. So there is a lot going on in the product space right now. We have over 30 states with either proposed or adopted laws banning the intentional use of PFAS in a variety of different products. Again, the definition of PFAS rears its ugly head here. Now, all of the states have adopted the same definition, and it is the broadest definition being used across the globe today, to the best of my knowledge. This snapshot here gives you some idea of the scope of these legislative efforts to enact bans or prohibitions or restrictions. And this is on the manufacturer, sale, distribution, or use of products containing intentionally added PFAS. so that ranges from firefighting foams to different textile products, juvenile products, food contact materials, cosmetics, cleaning products, and the like.

Now, they all use the same definition for what constitutes intentionally added, although they don’t reference a limit of any kind as to what’s reflective of intentionally added. Some do go as far as to say intentionally added and present in any amount, or in the rare case of California they say intentionally added or total organic flooring present above a hundred parts per million. So they’re the one state to draw a line in the sand about maybe what’s reflective of intentionally added. The way the laws are written has left a lot of question about what it is we’re to represent and how in terms of generating compliance data. The language is just so broad and brief to address what is an incredibly complex matter. It’s also important to recognize that the product space is a bit different from the environmental space that we’re so accustomed to where we’ve got regulations governing our business. In this case these are laws governing their business, and the regulatory agencies have yet to decide if or how they’ll build a regulatory framework for assessing compliance with these laws.

Now, that doesn’t mean companies are off the hook, of course, right? Any researcher, NGO, attorney general can decide to randomly start testing products to ensure that they’re in compliance with these laws, and of course, this is happening as we continue to see this reported on in the news and court filings all the time. Lastly, with all these reporting requirements and requests abound, I thought I’d just mention this relatively new EPA tool that consolidates PFAS data from 11 different databases into one nice searchable platform. So I know a lot of you are struggling to find more info on sources of PFAS. So as these laws go into effect, you’ll probably want to continue to check in with this tool and see what starts to emerge.

OK, lastly, I’m just going to spend a little bit of time on method development updates, and how these kind of align with supporting that plethora of regulations that we just talked about. So draft method 1633 is specifically for PFAS analysis in non-potable water, soils, biosolids, landfills, leachate, and tissues. This is a targeted analysis for 40 PFAS and it fundamentally aligns with the user-defined methods that have been the basis for PFAS testing for the last two decades, so we do expect a certain degree of comparability in the data sets as we transition from one method to the other. The draft method is currently on its fourth revision as of this summer. Probably the most significant update to the latest revision was to finalize the limits for the non-portable water matrices. EPA anticipates releasing the final draft for public comment before the end of this year. Then of course there’s the public comment period which is usually about 60 days and then we’ll have to respond to the comments, finalize, and publish in the CFR or the Code of Federal Regulations. EPA has also released a draft method for adsorbable organic fluorine or AOF.

That’s draft method 1621. This method applies to aqueous samples only. As far as I know, EPA has not begun to tackle a draft method for EOF, which would be for solids. This method has just begun the multi-lab validation effort, but the EPA has noted that they’ve begun using it in their wastewater monitoring efforts to gather data that’s going to help inform those future effluent limitation guidelines. So this means, I’m guessing we’re likely to see the real-world application of this method, maybe before it ever even gets published. So, never a dull moment with PFAS. In the US, most of our work is still supported by those user-defined methods, often referred to as 537-modified, but slowly but surely we’re going to see a transition to that draft 1633. In fact, I suspect pretty rapidly once the method is actually published the CFR. However, there are some recent publications of ASTM methods floating around out there, mostly repackaging of older ASTM methods, but I thought it would be helpful if I spoke to these as well.

So there’s method 8421, which is basically a copy of EPA 8327, an older EPA method that was never really widely adopted. What’s distinctive about this method is that it utilizes direct injection as opposed to solid-phase extraction, essentially cutting out a prep step. Because of this, there’s a company that has marketed this as a screening tool. In fact, it really is not as written. It will produce fully quantitative results, and if you’re a lab like ours, you would only perform it using isotope dilution quantitation, making the results that much more defensible. So the reality is you could take any fully quantitative method and run it in a way as to more screening quality or semi qualitative results than definitive results so you know that logic can be applied to any of our methods and 8421 is not inherently written as a screening method. And then hot off the presses they just publish method 8535 which again as far as I can tell is just kind of a repackaging of an older ASTM 7968 method but for a longer analyte list. This is specific to soils and biosolids, but it does not use isotope dilution.

With the EPA method 1633 validated for soils, biosolids, non-potable water, and more, and with it being very close to promulgation, I can’t really see what utilization there will be with these ASTM methods, but it’s always good to know what’s out there. Right now in the U.S. there is plenty of variability in target analyte lists between states or various agencies. But as we collectively transition to draft 1633, the 40 compounds you see in orange on the left are really starting to become the default standard when you don’t have a site-specific target analyte list that you need to achieve. That said, some labs can support much longer list of compounds like the additional ones you see listed here in white. Just keep in mind that to access those expanded lists, we’d still require those user-defined methods. And then in addition to the development efforts for PFAS in those traditional water and soil matrices, there are methods that have been modified for PFAS that source air emissions, ambient air, soil vapor, indoor air. So EPA set out to tackle source air first, largely so that they can confirm that those destruction technologies are, in fact, destroying PFAS and not just creating unintended byproducts.

So, for source air, we already have method OTM45, which was designed to capture the semi-volatile PFAS we typically test for in waters and soils. And right now, they’re in the process of finalizing method OTM50, which targets the ultra-short chain or volatile PFAS that are expected to be those primary products of incomplete destruction. They are aiming for end of year to publish this method. and then next on their list is OTM-55 for the fluorotelomer alcohols, which will be further developed next year. And so then for the ambient air, vapor, indoor air, those are all still currently user-defined methods. When we move beyond our conventional tools, which was made up of targeted analyses, we find the non-targeted tools, and there are a few different techniques here, all of which user-defined again.

So building upon that targeted analysis, we can combine it with a preparation technique that tells us a little more about the unknown mass of PFAS in the samples, and we can do this using the top assay, the total oxidizable precursor assay. Something I really like about this tool is that it will not only represent the unknown PFAS, it’s not vulnerable to a high bias from identified non-PFAS compounds. Also we have really good sensitivity with this approach in that single digit per per trillion range. Now there are some efforts underway to develop a standard approach to this method as well. One of the primary concerns with this method is complex matrices because you may not get complete oxidation of the precursors because of some of those matrix effects. and also there may be transformation products that are not currently measured by this technique.

So some recent efforts have been made to improve upon this method. There were some multi-labs study that was done out of the Australian Land and Groundwater Association. STIRD-UP ESTCP has funded Dr. Sedlak’s group out of UC Berkeley to enhance the performance and predictability of this test. That research is ongoing, I believe, and then the EPA is also working on standardization for this method as well. And then when we look to capture more of the unknown mass of PFAS, we find ourselves turning to something like a total organic fluorine measurement using combustion ion chromatography. This is really just an approximation of all PFAS using the organic fluorine content of the samples. So if you run this method on waters that would be absorbable organic flooring, if you ran it on soils it would be extractable organic flooring. And as I mentioned the EPA is tackling a standard method for the AOF but nothing yet for the EOF. And something to be aware of about this technique is that although it’s the best available technique for a proxy for total PFAS, the representation of PFAS only or all PFAS is not foolproof. You could have a low bias from missing things like the short chains. You can have a high bias from things like fluorinated pesticides or fluorinated pharmaceuticals. And the sensitivity is more like a part per billion as opposed to that part per trillion range.

And then lastly, you’ve got this non-target analysis approach using high resolution mass spec. And it’s important to know that this is a really sophisticated tool, not only from the standpoint of generating the data, but maybe more so from the standpoint of interpreting the data. And these are the type of data that are typically used in things like forensics investigations, maybe ultimately in litigation. And there are some efforts underway to develop standard approaches to not only the analytical, but maybe more importantly to the data interpretation. So I mentioned a significant challenge is the process of interpreting the results. And some of that comes down to just how we present the results and our process for making certain determinations. So this paper expanded upon the Shamancy scale and set out to harmonize the approach for communicating about PFAS identifications. And so they’ve created this new confidence scale with criteria that hopefully we’ll start to see the laboratories adopt and develop some standardization between us.

And with that, we are at the end of my updates for today. So thanks so much for your time and attention. All right.

Thank you very much, Taryn.