Challenges of PFAS in Groundwater: Lessons Learned from Michigan’s Survey of Community Water
Learn the Following in This Free Webinar:
- Discovery of unacceptable levels of emerging contaminants like per- and polyfluoroalkyl substances (PFAS) in a community water supply
- Immediate and longer-term actions to protect public health and ensure a reliable supply of safe drinking water
- Lessons learned during Michigan’s survey of all its community water supplies in 2018
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Dane: Hello and welcome, everyone. My name is Dane Menke. I am the digital marketing manager here at REGENESIS and Land Science. Before we get started, I have just a few administrative items to cover. Since we’re trying to keep this under an hour, today’s presentation will be conducted with the audience audio settings on mute. This will minimize unwanted background noise from the large number of participants joining us today. If the webinar or audio quality degrades, please disconnect and repeat the original login steps to rejoin the webcast.
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Today’s presentation will focus on challenges of PFAS in groundwater and lessons learned from Michigan’s survey of community water. With that, I’d like to introduce our presenters for today. We are pleased to have with us Steve Sliver of Michigan Department of Environmental Quality. Steve Sliver has 32 years of state government experience and is the executive director of the Michigan PFAS Action Response Team or MPART. He was assigned to MPART in April of 2018 where he served as Michigan DEQ’s senior representative within the organization. In that role, Steve Sliver led several major MPART initiatives including the recently completed sampling of public water systems throughout the state for PFAS.
We’re also pleased to have with us today Patricia Byrnes Lyman, investigation and remediation manager at Michigan Department of Military Veterans Affairs. Patricia Byrnes Lyman has over 25 years experience in the environmental industry and has worked as an environmental engineer for multiple large international environmental consulting firms, contributing technical input on commercial, military and industrial facility projects throughout New England and Michigan. In her position with the Michigan Department of Military Veterans Affairs, she’s the PFAS lead and manages environmental investigation and remediation efforts across the state at Michigan Army National Guard facilities.
We are also pleased to have with us today, Ryan Moore, Great Lakes district manager at REGENESIS. Ryan Moore has 18 years of experience as an environmental project manager and laboratory account executive relating to multimedia contamination sites throughout the U.S. His experience is focused on-site investigations of soil and groundwater contamination, corrective action evaluations, operation and maintenance of remediation systems, large soil removal remedial projects, institute groundwater and soil treatment, vapor intrusion assessments and environmental laboratory operations such as QA, QC evaluations, data interpretations, and business development.
All right. That concludes our introduction, so now I will hand things over to Steve Sliver to get us started.
Steve: Okay. Thank you, Dane. I appreciate the opportunity here. Good afternoon everybody. I’ll start out with just a little bit of background on the compounds we’re talking about. Many of you already know a lot about these, but the Per- and polyfluoroalkyl substances or PFAS for short. These compounds enjoy one of the strongest bonds in chemistry, the carbon-fluorine bond. They act as suffocants. They are hydrophobic and oleophobic, which means they don’t like water or oil. They act as suffocants like detergents, wetting agents, emulsifiers, foaming agents and dispersants. We’ve been developing these back in the 1940s and there’s over 5,000 of them today. So I want to start out as well with some common PFAS abbreviations because we’re all guilty of over-generalizing and when we talk about PFAS, we’re really only talking about a few of them that we have much [inaudible 00:04:30]
The first two here you see PFOA, PFOS. Those are ones that nowadays are not as much in the marketplace. They stopped making those and using them and we now are dealing with replacement compounds. But the PFOA way that was used in Teflon, for example, PFOS in Scotchguard. And some of the other ones you see here are others that we have more information on. We typically are looking right now for 14 or 24 of these compounds within that suite of 5,000.
So it’s often easier to talk about what PFAS may not be used in than it is to do an inventory of everything that they are. But everything from foams used for firefighting, mist suppressants for chrome plating baths, Teflon coatings on pans, stain resistant and water repellent coatings for fabrics. Even things like dental floss and the Rain-X that we put on our windshields to help the water bead. So why are we concerned about these? Well, they’re rather ubiquitous given all of the uses of them and they’re persistent. That strong carbon-fluorine bond means they don’t break down naturally very well out in the environment. And we understand that some of these, perhaps more than others, have a tendency to bioaccumulate buildup in our tissues and the tissues of other animals, fish for example, and they’ve been associated with adverse health effects. But equally as important is we don’t have all of the information we would like to have about their impacts on people and the environment. And we really don’t have what we would call a complete regulatory structure for them yet.
I’d like to show this slide here. This conceptual site model really shows the challenges we have in dealing with PFAS because essentially we are cycling them through the ecosystem. Since they don’t break down well and we’re not effectively destroying them, we’re essentially cycling them through. And a good example of you see in the middle of the page here is a landfill. Many of the consumer products, they ultimately end up in a landfill and some of the PFAS compounds may leach out of them and end up in the landfill leachate, which could go to a wastewater treatment plant, which may not be able to effectively remove all the PFAS compounds as much as we’d like. So they end up in the surface water and then they could end up bio-accumulating in the fish or going back into a drinking water supply or elsewhere into the ecosystem.
So in Michigan back in 2017, recognizing that the emerging nature or concern with these contaminants, we decided to establish a multi-agency approach which was rather unique within the nation. And this MPART is the acronym we use for Michigan’s PFAS Action Response Team. It’s comprised of representatives from multiple agencies within state government that are charged with protecting the environment, natural resources, overseeing agriculture, public health, even military and veterans affairs, facilities and airports and fire marshal. And essentially this team provides a multi-agency cooperative approach for all that we do in addressing PFAS throughout the state. Primary responsibility of this team is protecting public health, but when you’re dealing with an emerging contaminant, you also have to start at the beginning. Everything from how do we actually standardize our sampling and analytical to what do we do ultimately to prevent future contamination.
So I want to focus the rest of my time on what Michigan has done to evaluate drinking water. So in addition to investigating contamination at known or suspected sites of contamination and looking at what might be occurring in the surface waters and the discharges to those, we wanted to have a proactive approach to identify what the occurrence of PFAS are in Michigan’s drinking water supply and then do what’s necessary to reduce those exposures. And so last year we decided to sample all community water supplies within the state and then all schools and licensed daycares that had their own wells. That sampling effort was completed in December and the results from that effort will also be used to inform what we do next as far as additional sampling. So this is over 1,700 supplies. Michigan has another 9,000 non-community supply wells plus over a million private residential wells that may not ever be evaluated as part of an act of site investigation. So we’ll use these results to help inform where we go next with those.
So here’s the results. And overall we can say the state of the drinking water in Michigan is rather good. Ninety percent of the supplies that we tested were non-detect for PFAS. That means less than two parts per trillion of the reporting limit. And this evaluation was done using the EPA method 537. That’s the one the U.S. EPA recognizes for testing drinking water, 14 contaminants and 7% of the supplies had a concentration between non-detect and 10 parts per trillion total PFAS. And that 10 part per trillion is a number that our consultants and our MPART team agreed that if you stay below that for total PFAS, that’s a sum of all those 14 compounds that you likely are not dealing with a source of contamination that needs to be addressed today.
We had another 3%, which we call supplies within that middle bucket, about 62 supplies that had something more than that 10 but less than the 70 parts per trillion action level and those require some additional follow-up. And we only had a couple, which I’ll talk about as well that were over that 70 part per trillion, uh, lifetime health advisory level which Michigan has recognized. So the 10 to 70, that middle bucket, Michigan is now going to go forward and provide quarterly monitoring for the supplies that had something more than 10 and less than 70 PFOA, PFOS in any combination. We’ll do quarterly monitoring of those to verify whether the concentrations are varying over time. We’ll also work with them to make sure that customers are notified and if there are ways they can minimize exposure and also consider whether or not there are alternative water sources or treatments that they should be evaluating should the need arise. And so this quarterly monitoring that we’ll be doing over the next 12 months will cover the water supplies for 500,000 Michigan residents.
So the very small group of folks that may have more than 70 parts per trillion, that’s an immediate response. And we’ll talk a little bit about here where it’s more than notify your residents. It’s get them on alternate water right away and then address if it’s a municipal supply, what alternatives we have going forward. Also consider evaluating where that release is coming from and how to remediate it.
And I’ll mention now the one we had two supplies that had concentrations over the 70 parts per trillion. One is a school in an isolated area of the state and we are still evaluating that one that had only about a hundred parts per trillion PFOS. We’re not sure what the source is so we are actively investigating that and the students and teachers, approximately 300 people are on bottled water as we pursue that investigation. But the one that most of you probably are familiar with is the city of Parchment, Michigan, which was a supply serving over 3,100 residents in Parchment and Cooper Township. The back at the end of July last year, we found concentrations of PFOA and PFOS 20 times a lifetime health advisory level, and that required an immediate response. I share this timeline here just to give you an idea of how quickly things transpired from the time that we actually got the result on one afternoon to the residents being on bottled water the next morning and then after a series of transitioning to a new supply and verifying that that supply was acceptable from a number of drinking water quality parameters, they were on that new supply within a month.
So let’s talk a little bit here about what the municipal supply did. And this was the first example of what we’re aware in the country where we have totally shocked a system overnight and replaced the source water. They went from having three production wells one day to the next day being connected via fire hydrants temporarily to adjacent municipal supply from the city of Kalamazoo. And any of you involved in the drinking water program can well imagine, you know, the potential impacts and the concerns that you would have to ensure that you’ve addressed all the water quality parameters going forward.
So when you have contamination of supply wells for a municipal water supply, that also should trigger as it did in the city of Parchment, investigation of what impacts there might be on private residential wells. And as you can see from this diagram here, the three polygons, the blue polygons up in the middle left of the page, those are the supply wells for the city of Parchment. And one of the concerns or challenges we have had in Michigan as we investigate sources of contamination, impacted water supplies is how do we be strategic in trying to determine who else might be impacted and have an understanding of what the results might mean when we start doing testing around potential sources of contamination.
So in this case, what you can see is the light blue shaded area that is actually a mile radius around the wells that were impacted. And then that purple shaded area is the wellhead protection area for those wells. And so the first choice, not that it was going to be the end of all sampling, was to let’s first focus within that wellhead protection area a mile out and that’s where we began sampling. And what’s also important to recognize is when you get results, what is your public health action plan gonna be? That’s the second major component when we’re doing these investigations. When you get a result, what do you do with that result? And so here again, being strategic in your sampling, knowing where the groundwater flow direction is coming from and whether you do or don’t have a high strength source to deal with, you know, do you put the residents on presumptive remedies or bottled water depending on that result going forward? And so this is where the Department of Environmental Quality and Department of Public Health have been working very closely together to make sure that we have a very clear plan going forward so that we are number one, investigating the folks that need to be investigated and putting them on the remedies as rapidly as possible.
We also are concerned about the source. Once we’ve made sure that we’ve identified and reduced exposures in the municipal supply in any private residential wells in the area, is focusing on the source. And so you can see from this diagram here, there were numerous possible sources that might be influencing the groundwater quality for that municipal system. And so the DEQ’s role working closely with the local officials is to do file reviews, identify potential sources in the area, evaluate our hydrogeologic studies, what do we or don’t we know about groundwater flow direction and the different aquifers in the area, what sort of monitoring do we have and can we do some additional monitoring around these potential sources and then who are the responsible parties?
And this is probably a really good opportunity to point out that in many cases we’re finding throughout the state where we have essentially remediated what we thought were the contaminants in groundwater aquifers. And maybe decades ago we had sampled for and installed mitigation or remediation systems and thought we were done. Yet what we’re finding now as we go back to these potential sources of contamination is that PFAS have been behaving very differently in groundwater and soil. A lot of the models that we have to predict the plumes and characterize the contamination haven’t been working so well. Whether we’re not applying them correctly or the models themselves need to be improved. And that was definitely the case here as we see going forward potential sources where we had been monitoring and not noticing contaminants getting offsite.
I’ll talk a little bit about the keys to success in Parchment and first and foremost as you remember the timeline, it was a rapid succession of events triggered by the sample result. And we would not have been so successful as a community or state if it had not been for the residents in the city of Parchment and Cooper Township and the adjacent community of Kalamazoo working together to resolve things quickly. And I believe as well is the structure that we set up with MPART had been key to a rapid succession of getting solutions implemented in that community because we already had state agencies who were very well aware of what PFAS is and what we needed to do to address the contamination.
And as well, as you can see, this is just a picture here of a community town hall where we had 800 people. And what made that town hall I think very successful has been the actual presentations to all the residents from state, local and federal officials, all having a single plan which explained what we knew and what we didn’t know and what our proposal was going forward for doing the investigations. And being very transparent with the citizens, routinely communicating with them because there were a lot of things that we didn’t know. And so we went from actually having hourly to daily to weekly updates with the residents which we believe was very effective at keeping everybody on the same page in moving forward.
One thing that came out of this, which I think many communities can take advantage of as well, is that we kind of wrote the playbook on how to address not only PFAS but emerging contaminants that may come out of left field in a sampling event. And we actually have available now on our website a template for PFAS readiness plans where we’re encouraging communities with their own municipal supply to identify up front, okay, who would be involved if an event like this happened? What resources do we have? How would we even distribute bottled water? Do we have bottled water available to us? How quickly can we get it? And then not forget that there are helpful regulatory programs, especially the drinking water program where we have engineers and scientists who can assist communities as they explore ways to fix their system and provide drinking water to the community.
And just a few other quick takeaways here. We didn’t spend a lot of time on it, but specialized sampling and analytical. We are looking for contaminants that people have not looked for historically in the past and at very small levels in the part per trillion level. And that means that there’s not a lot of labs out there that can do this testing. And even the sampling protocols not only need to be established but followed carefully. When Michigan did some of the testing and especially when Parchment happened and we started trying to expedite samples at labs across the country, we were hearing from other states that the labs were backing up because of the burden Michigan was putting on them. And so typically today, given the capacity that we have at labs across the country, we’re still looking at three to four weeks many times for getting a result. So that’s something to understand it can be an ongoing challenge.
Also, as I mentioned earlier, the challenges of source identification and characterization. The PFAS contaminants are showing up in places where we wouldn’t necessarily expect them to be in and in areas where we thought we had cleaned them up or cleaned up other contaminants in the past. And again, some of the challenges, more studies are needed on how to better predict the environmental transport and fate of these contaminants throughout the ecosystem. And one thing we didn’t touch a whole lot on, but we are testing for 14 at least 14 PFAS contaminants. We have recommendations based upon EPA’s lifetime health advisory for two of them but you can imagine when other PFAS show up in those analyses that questions arise. And this is where our department of Health and Human Services folks really come into play to help communities and local health officials understand whether there might be any other public health response necessary to address some of these other contaminants where we don’t have a lot of information available.
And lastly again just to emphasize the important point of preparedness now that we’ve been through this once, we’ve learned some things and communities can develop their own preparedness plans based upon what we’ve learned. And here just to highlight as well, we’ve got a lot of information out on the web including results from our public water supply testing. And even as you’ll hear here shortly about some of the sites including, you know, Camp Grayling, we have a lot of information on the web that might be helpful to you. So what I’m gonna do now is transition and hand this off to Ryan and Patty. So thank you, everyone.
Ryan: Yeah. Thank you, Steve. This is Ryan Moore, the Great Lakes district manager for REGENESIS. I’m joined here with Patty Lyman. [inaudible 00:24:14] There we go. Again, I’m joined here with Patty Lyman with the Michigan Veterans Affairs, Military and Veterans Affairs office. We’re gonna talk about a site in Northern Michigan up in a Grayling Army Airfield, which is part of the Camp Grayling joint maneuver training center. Patty, could you just maybe give us a little bit of a background of the site and some of the challenges you’ve faced with groundwater remediation there?
Patricia: Yeah, sure. Ryan. I’d like to do that. So Camp Grayling has a very long history. It’s been in operation for over 100 years and it’s a very large area. It’s actually the largest National Guard training center in the country. It’s used for training for military staff, emergency responders, private sector, individuals from all over the world, and it’s also the home of the Grayling Army Airfield.
So the area that we’re doing our pilot study in is an area of a former bulk storage fuel facility. It was three above-ground storage tanks that we use for containing diesel fuel and that’s in the southwest corner of the Grayling Army Airfield. Generally the area’s flat. It slopes down to the south. Surficial geology is glacial outwash, sands and gravels, very permeable soils. There’s a non-continuous clay layer at about 25 to 27 feet and a second clay layer in some areas that occurs at 45 to 60 feet below ground surface. Groundwater is around 17 feet, varies a little bit but not too much. And groundwater flows to the south towards the Au Sable River.
It’s got a complex release history since it has such a long history of use. There’s been diesel fuel releases, there’s TCE and PCE releases that were associated with the cleaning of artillery vehicles and there’s PFAS that has been released as a result of some our training in the area. Most of these releases we actually don’t know the dates and the precise locations that they took place. Because of the complex number of releases and different compounds, there’s a complex remediation history. We started in 1984 addressing the diesel plume. The treatment technology has have changed over time once we established. There was PCE in the groundwater also. We changed the treatment technology and we established the locations of some precise PCE source areas. So we instituted some changes and resolved in that.
And then 2016 as a result of some DOD concern about PFAS being at military facilities, we sampled some of the groundwater existing groundwater wells in the bulk storage area and we got some detects of PFAS in those monitoring wells. In the following year in 2017, we did some vertical aquifer profiling along the fence line in this area and we did come up with some detects PFAS along the fence line border there. In 2018 we initiated this pilot study of the PlumeStop in the former Bulk Storage Area. And the intention of this part of the study is to polish the PCE plume that remains and also to investigate the effectiveness of the PlumeStop to address PFAS in the groundwater.
Ryan: Yeah. Thank you, Patty. You know, this is a little bit of a background on PlumeStop. Many of you guys have who are attending the Webinar, have either had PlumeStop applied at your site or you’ve looked at or evaluated it. And so I’m not gonna get into a lot of the history of PlumeStop, but I want to kind of get some of the basics of it. You know, it’s chloral [SP] activated carbon and what that means is it’s activated carbon particles milled down to very small size and scale one or two microns, which is the size of red blood cells. So it’s very, very small. It’s suspended in a water or polymer solution that helps with distribution widely at low pressure with traditional direct push methods or application methods. You know, no high pressures or fracking required to apply PlumeStop.
It acts extremely fast on the absorption side because of the huge surface area of the activated carbon particles. In essence, what we’re trying to do is convert the polluted aquifer into a purifying filter. Some of the goals when PlumeStop was developed was to treat the contaminant flux zones and to control back the fusion of contaminants from more low probable zones. In this slide kind of what you see here is the PlumeStop being applied through the sand, getting uniform coverage. Below it’s the clay that would act as the source of future back diffusion and then even up above the treatment zone can act as a future source of contamination. So again, we’re trying to treat that flux zone and prevent contaminants from moving on down the area. So back to, Grayling Army Airfield, again, here’s an aerial of the facility. We’re operating down in the southwest corner of the former bulk storage tank location.
So when Patty and I started setting Au Sable what we wanted to do is to toss kind of a simple plume cutoff [inaudible 00:29:37] and in this diagram here, it’s a series of injection points where we apply PlumeStop through the vertical treatment and then as contaminated groundwater passes through, we’re actually containing those contaminants and purifying the water. And so what’s to being discharged on the down gradient side of the treatment line is clean groundwater. And so this was kind of the concept of the test. And here’s a diagram. More of a little engineering kind of diagram. You see we had a series of nine injection points that are the orange diamonds and it’s about 45 feet across, I believe. We kind of did a little of a semi-arc application approach. This is just to account for any potential variation groundwater flow direction.
The blue triangles, those are the existing [inaudible 00:30:23] wells. We’ve got to upgrading on MW29A on that screen. We have 15 to 20 feet MW29B, the screen 21 to 26 feet. These are 5-foot intervals to kind of keep it in accordance with the DEQ’s requirements on monitoring at the site. In the center of the screen we’ve got two additional triangles. One is the blue, one is kind of a green colored. Those are about six feet of the injection line. And then on the far bottom side of the slide, we have two additional monitoring wells that are kind of about 16 feet away from the injection line to test, you know, how far down gradient we’re going to in the results.
You also notice here there are several square boxes. Some of them are black and some of them are kind of this yellow, orange color. These are our [inaudible 00:31:11] core locations where we actually advance the Geoprobe Macro-Core, hold a core sample and then try to visually say, can we see PumeStop? So we’re gonna kind of focus in on the SBA area in the corner right side.
On the picture on the left, that’s the core from SBA. The top right-hand corner of that picture is zero feet. In the bottom left-hand corner is the 30 feet. As you see, the black from the third core from the right is actually, we’re about 15 feet where you start seeing the PlumeStop show up visually. And then it continues all the way down to around that 26, 27 feet mark, where you start seeing the clay. What we also do, and we’re not only just visually looking at it in the core sample, but we’ll take a piece of soil and we’ll add it to [inaudible 00:32:02] with water, you know, usually every one or 2-foot interval and we’ll do kind of a shake test. And that’s what the picture on the right shows is when we take that soil sample, add it to water, shake it and kind of get a little separation and say how much PlumeStop is really showing up? Is it showing up on the interval that we are looking to treat?
And as you can see from 17 to 27 feet, we’ve got pretty good, pretty uniform coverage of the PlumeStop. The vial that’s labeled 15 feet, that’s actually Vado soil, so it was not in the groundwater, but what it does show is that you know, we’re not applying the PlumeStop above our target treatment interval. To kind of look at this again and back to what PlumeStop is designed for, again, we’re treating the contaminant flux zone that’s shown here, getting very good uniform coverage. We’re preventing back diffusion from that clay and a future day is it, you know, it starts to come back out or providing additional leaching foam above the treatment interval.
So let’s get into the results a little bit. It’s just a graph. We have about 132 days of post-application data. On the X axis we have the number of days post-application, and then on the Y-axis we have the contaminant concentration. And in this case, total PFAS on a nanogram per liter scale. PlumeStop was applied on day zero and then the first two sets of data points I’m providing here are the upgradient monitoring of location. So MW29A and MW29B. As you see it’s relatively flat, a little variation in MW29A but overall pretty consistent contaminants concentrations.
The next two sets of data that I’m providing are the near downgradient monitor locations and MW29A and MW29C. Both of these are six feet downgrading at the injection line. And as you see the first sampling event [inaudible 00:34:05] was about one-month post application, we had non-detect and has been non-detect for the PFAS contaminants throughout the duration of performance monitoring. And then MW29E, that is about 16-feet downgradient. Had a similar response as the two near downgradient monitoring locations.
And then we have MW29D, it looks a little different and that’s because we do not actually have a sample from the one-month post application event. When they went out to sample, it was observed that a little bit of PlumeStop was in that well and so the decision was made to not sample it until it cleared up naturally on its own, which it did before the two months post application event. When we did sample it, as you see, it went down to non-detect and has been non-detect ever since.
So we did mention this was a commingle plumes. So I definitely want to talk about the PCE results as well. Again, the X-axis is the days post application and the Y-axis is the contaminant concentration and in this case PCE and micrograms per liter scale. PlumeStop again was applied at day zero. And just like before I’m gonna show the first two monitoring wells are for the upgrading locations and again, very consistent, pretty flat, not many changes in the contaminant concentrations fluxing into the PlumeStop treatment line.
MW29 and 29C which are a 6-feet downgradient, again, one-month post application removed all PCE, dissolved PCE from the groundwater and has been non-detect ever since the first month. MW29E, this was 16-feet, had a very significant reduction, didn’t quite go to non-detect but a very nice dose response. But as you see the two months post application around 60 days, it did go to non-detect and then it’s maintained non-detect ever since. And then just like before on the PFAS results, the PCE sample was not collected from MW29D at the one month post application but when we did collect a sample, it was a non-detect and has been non-detect ever since.
So just kind of quick and summary, you know what this shows me is that like, you know, PlumeStop is a proven technology across the country for a lot of contaminants. But this specific study is kind of showing that we can eliminate risk of PFAS in groundwater. It’s a passive plume management strategy. What I mean by that is we’re not having any infrastructure we have to leave in place from like a large scale pump and treat system. There’s no long term monitoring and no going out, you know, once a week to just check our system. We put it in, we’re done. It’s easily implemented in the field. We can mobilize to many locations that could be very difficult to scale up a physical mechanical system. With PlumeStop and the way we apply it through direct push, typically we can maneuver a lot of areas that other, remediation mechanisms may not be as ideal. When compared to pump entry, it’s can be very cost effective. Again, you don’t have any of those long-term maintenances or weekly visits to a site to address this.
And it will last for decades. I know we didn’t get into some of the isotherm data now on PlumeStop related to PFAS, but we’ve done several technical bulletins, previous webinars that we’ve had that will get into this. And two, we can provide some journal articles that are being completed by third parties that are peer-reviewed and scientifically published. That kind of gets into the longevity of PlumeStop related PFAS. So if you’re interested in that, we can definitely provide that after the Webinar here.
So kind of next steps. You know, some of the things we’re trying to expand upon the field test right now. Some additional monitoring wells are going in this week. Some side gradients, upgradient wells and some additional downgradient wells, kind of get a better handle of the specific groundwater flow in that region and that specific kind of bulk storage area. And then there’ll be a future sampling event as well. Patty, do you want to kind of maybe talk with us a little bit about your activities moving forward on a remedial investigation and kind of strategies you guys are looking at?
Patricia: Sure. So we’re early on in the investigations at the airfield and at Camp Grayling in general. As I mentioned, they only discovered PFAS there a little over two years ago now. And so at the airfield, we’ve completed the field work for the outside investigation but that’s being conducted through…by the National Guard for the DoD and they haven’t finished the report yet. So I actually I’m not privy to the results of that investigation as of yet, but we’re fairly certain we’re gonna move on four to a remedial investigation at the airfield but that’s still in the planning stages.
Ryan: Yeah. Thank you. So with that, I think we’re on our question time period.
Dane: All right. Thank you very much, Ryan. That does conclude the formal section of our presentation. And at this point, we are ready to shift into the question and answer portion of the webcast. Before we do this, just a few reminders. First, you’ll receive a follow-up email with a brief survey. We really appreciate your feedback so please take a minute to let us know how we did. Also, after the Webinar, you’ll receive a link to the recording as soon as it is available. All right, so let’s circle back to the questions. Let’s see here. First question, this is for Steve and the question is, what is MPART doing to evaluate treatment options for drinking water and waste streams?
Steve: Okay, thanks for that question. So we’re doing a couple of things. Within MPART we have a workgroup comprised of representatives of our Department of Environmental Quality and health and human services and others. That is a clearinghouse to both inventory and evaluate various treatments and remediation technologies. And so, in addition to that, we also are working with a professor out of one of Michigan’s universities to help us evaluate different technologies and identify where more research might be needed. We know that many view the options as limited today to things like granular activated carbon, reverse osmosis and or ionized resins and we might be very limited on the destruction technologies. So another thing that we are doing as well as we’re getting ready to establish a roundtable of various representatives from waste disposal industry, manufacturers and academia to determine what the technologies are out there today and where we believe we need more research and who can actually help fill the gaps of where the research is needed.
Dane: Okay, thanks, Steve. Next question also another one for Steve and the question is, is Michigan pursuing an MCL for drinking water and PFAS levels?
Steve: Okay, so at this time we are not formally pursuing a standard for drinking water. But with that said, as we talked about earlier, Michigan has been…we’ve essentially adopted the lifetime health advisory recommendation that’s issued by EPA for PFOS and PFOA. Any combination of those at 70 parts per trillion. And I guess more important than that is all of the work that we’ve done so far, both in investigating and remediating or mitigating any of the contamination. We’ve been able to do that without actually having an enforceable standard under the drinking water program. We have in Michigan enforceable standards for groundwater protection of drinking water at 70 parts per trillion for those two compounds as well as we have enforceable standards in our surface water program of, for example, PFOS at 11 parts per trillion of a discharge into the surface waters, any wastewater effluence. And we’re using those standards to both identify and reduce any of the concentrations we’re finding out there in the environment while we are considering what sort of standards we might need in the drinking water program.
Dane: Okay, thank you very much. So here is another question for you Steve, and that question is, what are you doing about contamination in surface water across the state?
Steve: Okay, I just alluded to that a little bit. So in Michigan, we have enforceable standards for both PFOS and PFOA in surface water. And so a couple of things that we’ve done in Michigan we’ve been doing for the past several years. Number one, we’ve integrated the analysis of the PFAS compounds into our ambient water testing where we go around the state on a routine basis and analyze waters and various watersheds for a number of different contaminants. And we’re using that to determine number one, you know, are there any concentrations out there outside of what someone might consider a manmade background, which by the way, in Michigan we believe is probably closer to the non-detect two-part per trillion range. And if we are in an area and through this ambient water testing, find something higher, for example, like 40 or 50 that then triggers an evaluation within the watershed looking upstream on what some of those potential sources might be.
We also have asked all of our wastewater treatment plants, the other [inaudible 00:44:25] treatment works and their industrial pretreatment programs to look upstream at their industrial users, to screen them or whether or not they might have PFAS on their discharge. And if they do to require them to test and if they find it to look at ways to reduce the amount of contaminants coming into the headworks of the wastewater treatment plant and in general just to reduce further any inputs of PFAS contaminants into the waterways and the state.
Dane: All right, let’s see here. Next question is for Patty. Patty, the question is, what are the future remediation plans at Camp Grayling?
Patricia: That’s an excellent question. Right now we’re in the very early stages of the investigation. As I said, it’s going through the circle process through the DoD and the National Guard Bureau. So, we really, really can’t make any long-term plans until we determine magnitude and extent which we’re in the process of doing now. So our future actions are going to be determined by what we find in the next year or so in the field work.
Dana: Okay. Thanks, Patty. Next question here is for Ryan. Ryan, the question is, what states have approved the use of PlumeStop on sites?
Ryan: Yeah, good question. You know, PlumeStop has been around for four or five years now. It’s widely accepted across the U.S. It’s been applied throughout here in the Midwest where I’m located, you know, Michigan, Ohio, Indiana, Wisconsin, Illinois. So it’s pretty widely accepted. I don’t know of any states who have not approved it. Typically, state agencies wanna have a little bit discussion about what’s in it and how does it work. But other than that it’s pretty widely accepted.
Dane: Okay. Thanks, Ryan. Back to Steve. Here’s another question for Steve. The question is, was the sampling from your community survey, was that sampling from finished water or raw water?
Ryan: So it depends on the supply. So all of the, I believe we have 75 systems that have surface water intakes. So in those systems, we did a sample of the intake and of the finished water and generally, all systems with finished water were tested for that as well.
Dane: Okay, great. So here is another question for you, Steve. And the question is, did you take into consideration the types of wells and construction materials into the results? And they give it as an example, some wells have Teflon tubing for example.
Steve: So basically our focus has been on what the consumers of the water supply were exposed to. And so you’re right that there could be some potential contamination there. And I think more at the residential level if there were ways to screen out those sorts of influences but when it came to the municipal water supply, we were testing the finished water regardless of what the components were of the system. So the results, all are finished water that is being distributed out to the residents.
Dane: Okay. Thank you, Steve. Oh, let’s see here. Next question is for Ryan and the question is, with PlumeStop, what happens to the PFAS that is captured in situ? Does it stay captured for perpetuity?
Ryan: Yeah, good question. You know, so activated carbon is kind of a dynamic system and so there’s always some coming off and some coming back on or being absorbed onto the carbon. We talk about like what’s the longevity of it. This gets into a lot of our isotherm studies that we’ve conducted and in most cases where the PFAS contaminant levels down in the part per trillion range, we’re gonna be able to hold on to those compounds for decades. And some of the studies are upwards of 50, 60, 70 years so, you know, it’s always going to have a little bit of movement in there and that’s just the nature of the PFAS and so get a destructive mechanism in place. Eventually, if you’re just doing a treatment line or a treatment barrier, eventually it will fill up and that would release contaminants. The question again is how long and in most cases, if we’re gonna be able to lock this up for decades to allow for time for remedial investigations, looking at other ways to provide water, etc. Good question.
Dane: Okay, thanks, Ryan. Now here’s another question related to PlumeStop and that is, does PlumeStop work with other contaminants? And as examples, they give non-organics and metals.
Ryan: Yeah, good question. Traditionally we’re using PlumeStop with the organics. So ordinary solvents, you know, lower levels of benzene, PFAS, PCBs, anything that can be absorbed by activated carbon could definitely be utilized for treatment in PlumeStop. Some of the metals do have some affinity to activated carbon. It would be a case by case basis. A lot of times it’s based upon the species of the metal, we would want to work with our R&D department to see if it’s applicable to a specific metal that you would be or specific inorganic that you’re trying to target. In general though, if it has affinity, if the compound has affinity to activated carbon, then there’s probably some applicability of PlumeStop.
Dane: Okay. Thank you. Here’s another PlumeStop related question, Ryan, and that’s do you have success in fractured bedrock environments?
Ryan: Yeah, absolutely. I mean, as like I said, PlumeStop has been widely accepted, so it’s been applied on a variety of types of sites including fractured bedrock. I’ve worked on a couple of sites, so you know, up in Wisconsin and some other locations where they had, you know, some fractured sandstones, and we’ve applied PlumeStop and it’s been absolutely great for those settings. You know, in general, if you can inject water, you know, you can inject PlumeStop. It’s very…similar consistencies. And so it’s just a matter of the delivery and understanding with a fractured bedrock, understanding those fractures, you know, where are they at, where do they go, what are they connected to, which anyone who’s working on fractured bedrock sites understand the difficulty of that characterization but there is applicability with PlumeStop and fractured bedrock.
Dane: Okay. Thanks, Ryan. Let’s see here. Next question. This one is for Patty and it is, has there been any coordination with federal agencies or feedback from them regarding anything from the sampling methods or analytical methods used or for remediation success, and or challenges?
Patty: Okay. So in terms of the PlumeStop pilot study, we discussed it with the DEQ, our local state agency, and they gave us consensus to go forward with it. We also, part of the funding for the PlumeStop pilot came from the National Guard Bureau, so they’re completely aware of the process and provided some funding to focus primarily on the PCE portion of the, of the plume but it involved in the installation of the PlumeStop. Because in terms of the general investigation at the site, right now the site is being investigated by the National Guard Bureau, and through the circle process. So we’re using slightly different parameters on our analysis at least in the first phase and the site inspection process. We’re not using the same parameter list that the state uses. We’re using the EPA and DoD list of PFAS parameters.
Dane: Okay. Thanks, Patty. Let’s see here. Next question is, it’s probably mainly directed to Ryan although also perhaps Patty. The question is what are the vertical…it’s regarding the Camp Grayling case study. What did the vertical profiling show in relation to the migration of PFAS?
Ryan: Yeah. Good question. You know, on this site we were not able to do some of the more higher res flux studies that we would maybe do on some other PlumeStop sites. But what we did find when we did our vertical profiling was pretty relatively uniform sand from that where groundwater started at around 16, 17-feet, 17 feet down to the clay, which was again right around 26, 27.
There was a little [inaudible 00:53:38] thing in some of the areas, but overall it was relatively uniform. And then we have the kind of a clay confining layer in the area we were at. So a lot of PlumeStop sites or PlumeStop projects. And so people, someone who who’s asking this question might be more familiar with some of these other sites where we’ll actually put in some passive flux meters and try to get an idea of a contaminant flux or groundwater velocities within a more narrow range of say, you know, every 5 feet or every 2 or 3-feet. On this site, we weren’t able to do that. We were kind of limited in some of the, you know, we have some limitations on being able to employ some of those higher res characterization. Good question though.
Dane: Okay. Thanks, Ryan. Let’s see. Next question is another question for you Ryan. It is in a commingled plume situation, do you find PlumeStop remaining effective for similar durations between the different contaminants? And they give us an example PCE and PFAS.
Ryan: Yeah, a great example. You know, I believe, and I’d have to look at some of the isotherm data that confirmed this, but I believe, you know, like, PFAS has a little bit higher affinity towards the activated carbon. You know, like PFOS for example, would have higher affinity than I think the PCE does.
The most thing that matters the most are the starting concentrations and then the groundwater velocities. And so what’s that max flux coming through the area? So for this situation, if the PCE was an order of magnitude higher than the roughly 10 parts per billion that we were applying at, say it, you know, then it could have a less effectiveness on the PCE and actually start breaking through if we didn’t adjust the carbon content or the PlumeStop content. So it can be just as longevity with, you know, the organics as with the PFAS.
One of the things I want to point out is that the PC or like petroleum hydrocarbons, they’re destructive mechanisms that we can co-apply with the PlumeStop. For example, we can add our MicroZVI with the PlumeStop for the PCE and address that contaminant. So then it’s no longer exhibiting a demand on the PlumeStop system so it can focus in kind of sort of speak on that PFAS.
Dane: Okay. Thanks, Ryan. Let’s see. This question might be for Steve and it is, what testing methods would you recommend to demonstrate the potential efficacy of PlumeStop given a site’s unique groundwater flow and geological conditions?
Ryan: Yeah, I can take this. When we’re talking about testing for PlumeStop, you know, sites, we’re looking at a lot of factors and so, you know, we may look at it like total organic carbon. We’re gonna look at non-target compounds. So if it’s a petroleum situation, you know, you’re not just looking at benzene, you want to look at TPH. If it’s commingled with heavier compounds such as the PH is, or naphthalene we want to look at that. So we want to look at everything that could exhibit demand on the activated carbon, not just the specific compounds we may be targeting.
Again, we also want to evaluate what the aquifer is doing. So we want to look at geochemistry, you know, sulfate, you know, some of the iron, ORP, pH temperatures. So we want to get an idea if it’s a compound that we can biodegrade. Do we want to go that approach? You know, what conditions aquifers start with? What are we going to do to get it optimized for biodegradation? Yeah, if it’s just PFAS related, again, we want to identify is this commingled, are there other VOCs? You know, fire training areas potentially have a lot of commingled stuff there because what do they do? They add a bunch of fuel, they light it on fire and then they try to put it out with these firefighting foams and so it’s naturally going to have, you know, benzenes or TPH something in there that’s gonna exhibit demand. Those compounds may not move as far from the area like PFAS, but they still exhibit demand. Good question.
Dane: Okay, thanks, Ryan. Let’s see here. Here’s another question and this one is a for Patty and the question is, did PFAS contamination at Camp Grayling demonstrate any distribution trends? And the example that they say is laterally or vertically independent of groundwater flow direction.
Patricia: Of the data I’ve seen, no. It’s generally a following groundwater flow direction quite precisely. And as I said, we have recently finished the initial subsurface investigation on the airfield and I don’t have the detailed results back. The final report on that won’t be published probably until mid to late summer. So I don’t really have enough data to make a knowledgeable statement about that.
Dane: Okay. Thanks Patty. Let’s see here. Next question. It looks like we’re just about approaching out of time, but perhaps time for at least one more. This question is for Ryan and it is, is PlumeStop effective on higher initial concentrations of PCE? What is the upper limit?
Ryan: Yeah, I mean, a lot of it just kind of depends on what are your site goals on and where are your receptors at in relationship to these high concentrations? You know, PlumeStop is very effective when used in combination with other mechanisms. And so if you’ve got maybe a Dean Apple [SP] situation, maybe PlumeStop is not appropriate in that specific zone. It might be more appropriate to be downgraded a little bit and then maybe combine that with a chemical oxidation approach or mechanical system approach or escalation for the higher concentrations. And then you kind of utilize PlumeStop where it fits nicely.
So I don’t want to get into like just trying to say it, put a number on it because it’s used in a lot of places. You know, if your reduction is only at 50% goal, then obviously it can be used at a higher concentration than if your reduction is three [inaudible 01:00:09] magnitude, right? So if that was your goal. So it depends on the site. It depends on the setting. You know, there’s a lot of factors so it’s hard to put like a specific number. But yeah, you know, there’s things we at REGENESIS we can take a look at for people and help them with the evaluation process and look at the site information and try to understand your goals. And then just try to see if it’s appropriate or not for your side.
Dane: All right. Thank you so much. And we are out of time, so that’s going to be the end of our chat questions. So, if we did not get to your question, someone will make an effort to follow up with you. If you’d like to learn more about remediation solutions from REGENESIS, please visit regenesis.com. Thanks again very much to our presenters, Steve Sliver, Patricia Byrnes Lyman, and Ryan Moore, and thanks to everyone who could join us. Have a great day.