 Hello, I'm Chancellor Rodney Bennett. Thank you for joining me for today's Nebraska lecture. Since 2003, this distinguished lecture series has elevated some of the University of Nebraska-Lincoln's most notable scholars, researchers, artists, and thinkers. Faculty who live our university's land grant mission every day and make a positive impact on our communities through their work. Committed to making Nebraska our nation, our world a better place to live, our lecturers are experts in their fields devoted to mentoring and shaping future generations and solving the most pressing challenges our society faces. They truly embody the spirit of our flagship university's land grant promise to Nebraska and the world. I am pleased to be able to share this distinguished lecture series with the broader Lincoln community and beyond. It is truly a celebration of our three primary missions of research, teaching, and service. And I'm so proud of our faculty's accomplishments and their dedication. Thank you to the Office of Research and Economic Development, the University's Research Council and the Osher Lifelong Learning Institute for partnering to sponsor this lecture series. I hope you enjoy today's lecture. Good afternoon, I'm Shannon Bartelt Hunt, Professor and Department Chair in the Department of Civil and Environmental Engineering. And I was so pleased to be asked to give the 2023 Nebraska lecture. I've been at Nebraska during my professional faculty career and I'm really excited to talk to you today about my research which focuses on our water and how it affects our health. So one of the first points I'd like to make is that while we have a renewable system for water, it's a very finite resource. So I love this slide. It's our good old water cycle that many of you probably saw in fifth or sixth grade. One thing I like about this water cycle as opposed to what you might have seen previously is that it updated to include human impacts on water. So this water cycle of course includes precipitation which falls to land, that water flows over the ground, into our surface water and infiltrates to our groundwater. But it also shows those human impacts on water, our agricultural use of water, our municipal use of water, and our industrial use of water. Something that's very important to note is how limited our water resources actually are. This is a graphic from the USGS that just shows the scale of the earth. That large blue water bubble is how much water is on earth but that includes all of the salt water and water that's not really available for us to use. That small blue bubble right next to it is fresh water and that very, very, very tiny blue dot that you may not even be able to see just below is actually the fresh water that's available for us for all of human use on our earth. So although our water is renewable, it's a very, very limited resource. One of the factors that my research involves is looking at sources of water contamination. So we have different ways that our water can be contaminated. We use chemicals in industry. We use it for agricultural production. We release chemicals from our own bodies when we take medications and all of those compounds end up into eventually into our water supply. There's different types of water contaminants that we are interested in as environmental engineers. These include organic contaminants, microbial contaminants. There's geogenic contaminants. These are things that are present naturally in the earth's surface like arsenic and uranium but if they get into our water supply can cause us health problems. We're concerned with metals, nutrients, even temperature of water can be considered a contaminant. But the two contaminants that I'm gonna talk about today are plastics and pharmaceuticals and personal care products. These are compounds that we consider to be emerging or newer contaminants that we're just finding in water over the last 10 or 15 years and are finding that there can be health effects of these contaminants at very low levels. We know our health is very dependent on our environment. This is just one example of how that is the case. So in the United States, there's nearly 15 million households that use private wells for their drinking water supply. And then the state of Nebraska, we have many residents who use private wells for their drinking water. And across the U.S., we estimate that over 20% of private wells contain at least one contaminant that can cause health concerns. This map in this figure shows nitrate levels across the United States. And you can see Nebraska is largely under that red and yellow shaded portion, which just shows we have very high levels of nitrate in our water. And we know nitrate can lead to certain health impacts if we consume water in excess of contaminant levels. Another area that you may be less knowledgeable about is how antibiotics in the environment can contribute to human health. So we know that there's a hospital-induced antibiotic resistance. But researchers are also finding that there could be antibiotic resistance that's coming from environmental causes as well. So we use antibiotics in animal production. We consume antibiotics ourselves. It's very important that we have antibiotics when we have infections to be healthy. But both us and animals release some of those antibiotics in our wastes. Those can find their way into the environment and then they can result in increased antibiotic pressure for bacteria resulting in antibiotic-resistant bacteria. So in Nebraska, we've looked at the presence of antibiotics and antimicrobials in livestock production. It's important that we have antibiotics for livestock production. They're important for treating disease. We also use antibiotics prophylactically and for growth promotion. But all antibiotics are not designed to be completely absorbed. So some of that antibiotic compound is going to pass through an animal or through us as a human and be excreted in wastes. Our wastes, human wastes, go to municipal wastewater treatment plants, but often animal wastes are land-applied as a fertilizer. Applying manure to land can be an excellent way of obtaining additional nutrients and avoiding commercial fertilizer production. But those animal wastes can also contain trace levels of these antibiotics. One of the concerns that we have with antibiotics in the environment is the issues associated with antibiotic-resistant infections. So we're spending about $20 billion in excess healthcare costs due to antimicrobial resistance. And one of the concerns is you can have bacteria in the environment which can receive antimicrobial resistance genes through a process of gene transfer, which can be caused by the presence of these environmental antibiotics. So a study that I conducted with collaborators a couple of years ago was to look for the presence of antimicrobials and antibiotics in two Nebraska watersheds. So we looked at the Elkhorn River Watershed, which is just north and west of Omaha. And we also looked at the Shell Creek Watershed, which is more in central Nebraska. We were interested in these two watersheds because the Elkhorn River Watershed has a lot of people as well as animal production activities. It also has a municipal wastewater treatment plant from in Fremont, Nebraska, whereas the Shell Creek Watershed is largely agricultural, has about one million head of predominantly cattle and swine, row crop production in only about 1,500 people. So not as much municipal wastewater input. So what we did in these two locations was we sampled water that flowing through Shell Creek or flowing along the Elkhorn River at various times throughout the year. And we did this at different locations. And so what you can see here on the left is data from the Elkhorn River. And the second location, the wastewater treatment plant, as we would expect, had relatively high levels of antibiotics present in the water. But we did detect antibiotics in both locations, both the Shell Creek Watershed and the Elkhorn River Watershed, across various times of year. So what this told us is that, yes, antibiotics are present in our surface waters in Nebraska. We detected a total of 31 different antibiotic compounds. And importantly, six of these have uses for human disease treatment. So compounds you might find in your medicine cabinet or might be prescribed by a doctor when you have an infection, things like sulfanthoxazole or tetracycline. We found these in these surface waters. As I mentioned before, much higher concentrations were associated with that, the effluent or the discharge of that municipal wastewater treatment plant. And that's to be expected. Those plants were not designed to remove these types of trace compounds. So it's typical that they would pass from the untreated wastewater through the treatment plant and be discharged. And we also found some seasonal variability. And this is important. We found higher concentrations in the fall, in the Shell Creek Watershed. And so that gives us some insights into what times of year we might see higher levels of antibiotics. To go along with this, we didn't just sample for antibiotics. We also wanted to look for the presence of antimicrobial resistance genes, as well as bacteria. And so there were few bacteria that were detected that do have a concern with respect to human health. So things like aeromonas, E. coli, these types of bacteria are known to cause human infections. And what we found is that all but four of these bacterial isolates contained some level of antibiotic resistance genes. We found bacteria with these antibiotic resistance genes both in that wastewater treatment plant location, as well as other surface waters in both watersheds. And this really just shows the importance of looking for these compounds with a one health approach. So taking an approach that looks at the environmental occurrence, the potential human and animal health impacts, and relating this together. Another topic that I want to discuss with you is a newer type of contaminant that we are focused on at Nebraska, which is the occurrence of environmental plastics. So many of us use plastic every day in our daily lives. It's impossible to go to the grocery store and avoid purchasing something in plastic. And you can see that our global use of plastics has just skyrocketed over the past three years, past few years. Unfortunately, some of those plastics are not properly disposed of and can result in environmental weathering and breakdown and result in the occurrence of environmental microplastics. So you may have heard about environmental microplastics. There's been studies recently where they found them in drinking water, in people's bodies. And what microplastics are, are very, very small pieces of plastic defined as being smaller than five millimeters. So very, very small. The largest size you would be able to see with your, just with your eyes, smaller types of microplastics you have to use a microscope to detect. There's two different ways that microplastics enter into our environment. Some plastics are manufactured at these very small sizes. So in the past, we had products that contained microbeads in toothpaste and soaps and body scrubs. Those small, small beads were made of plastic. Those were actually phased out in the United States several years ago. We also have plastics that are generated by just environmental degradation. So if plastics are in the environment, they can be weathered by the sun, by thermal, by heat, and break these little tiny pieces of plastic can break off. They can be in our soil, they can go into the water and potentially cause some human health impacts. So ways that we're concerned that microplastics can interact with people. People can inhale them if they're present in air. They could ingest them if they're present in the water. If you're in contact with soil or in contact with water, they could come in contact with your skin. And there are not excessively clear linkages between microplastics and human health impacts, but things people are concerned about are things like neurotoxicity, carcinogenicity. And we certainly know with respect to animals, if animals like fish come in contact with microplastics, often they will consume those microplastics. That replaces their natural food and that can affect their metabolism and physiology. So something we were very interested in was whether microplastics would be released in biosolids that are applied to cropland. So again, going back to the concept of wastewater treatment, one of the products that's produced from wastewater treatment is a product called biosolids. And those biosolids contain nutrients and are often applied to crops as a nutrient source and a soil conditioner. One of our questions, but we also know that they can contain microplastics. So one of our questions is if we apply biosolids to cropland, do we see microplastics released in runoff and would those have the potential to impact our water supply? So we conducted a field experiment at the Rogers Memorial Farm at UNL with large plots where we established borders around areas of the field. We applied either biosolids, an animal manure, or we left some of the plots just with bare ground. So we had none of those amendments added to the soil. And then it rained over the course of a summer and every time it rained, we went out and collected all of the runoff that was channeled off of those plots into these receiving collectors. So what we found from this study was first, we had to look at our source material, what we were putting onto the cropland. And we did find, yes, there are microplastics both in the animal manure as well as in the biosolids. And this isn't terribly surprising. Other people have found the same result that there are microplastics in those municipal biosolids and also that there are microplastics in manure. And just like there are microplastics in people, right? When animals are being fed, there's probably small bits of plastic that might get into their feed. And so those are passing through their bodies just like they passed through ours. One aspect of microplastics that we're very concerned about is their different shapes. So what we found is that most of these microplastics were fragments, meaning they most likely were weathered from larger pieces of plastic. The second most common shape was a fiber and that probably was coming from something like our clothing. When we wash clothing, that wash water goes to our wastewater treatment plants and there are small fibers that are shed from our clothing when we wash it. So we did find microplastics in the source material and we knew the shapes of those microplastics. Then when we collected the runoff, we also detected microplastics in that runoff coming off of those crop fields. So we saw the highest concentrations in the plots that had biosolids amended. But we also saw microplastics present in our control plots, which really didn't have any kind of biosolids or manure amendment. And so that was interesting to us. We needed to sort out where those were coming from. We collected rainfall. There weren't any microplastics just falling with precipitation. That's a process we would call wet deposition. Were they being transported to those control plots by wind or could there have been microplastics already on the field from prior agricultural activities? This is something we still need to sort out, but it is important to note that while we saw elevated levels from the land applied materials, there were just microplastics present in the environment. And this is actually very common. In most environments we go to, we will detect plastics. The question for them is, what are those potential effects of the plastics in the environment? We also did some microscopy to look at the different shapes of plastics. So this slide shows you some images of a fiber, a microplastic fiber, fragment, films and foams. One thing we noticed is that the fibers and fragments, which are what we found in greater numbers in the runoff, had less bacteria on their surfaces. They were smoother. And we think some aspect of that surface roughness probably led them to be more easily transported in runoff compared with films and foams which had more bacteria on the surface and probably allowed them to be held in the soil more strongly. We also looked at the types of plastics. So because we find very, very small particles with a microscope, we don't know for sure that they're a plastic until we do some additional tests. And so we were able to determine the type of plastics and not surprisingly, we saw predominantly polyethylene plastics and that's very common for what we find in the environment because they're used in a lot of our consumer products and applications. We were also able to do, from our data, look at kind of a national level how many microplastics we would expect to be released from biosolids application. And we looked just at using biosolids on corn production. And so not surprisingly, the areas with higher biosolids correspond to those areas where we do produce the most corn. But just to provide a magnitude of from our study, which was taking biosolids, produced at a wastewater treatment plant, land applying them following techniques that would be commonly practiced, how much microplastics would we expect? And so we see that there can be quite a bit of release of these microplastics over the course of a growing season. And we also plotted those across the state of Nebraska relative to our waterways. So we know that we have a lot of surface water in these same areas where we're doing crop production. And so this just lends us to ask some next questions about how do we mitigate this? And we believe that there are great techniques that we already apply for other types of contaminants, which can also address these microplastics. So our takeaway message from this first part is that contaminants are present in our water at very low levels. So these antibiotics that I detected, these microplastics, are very, very low. If you took a glass of water containing those compounds and a glass of water from your tap, you wouldn't be able to tell any difference unless you did some analytical tests, chemical tests, or looked at that water sample under a microscope. But these contaminants can still have human and environmental health impacts. And I focus on looking at the occurrence of these contaminants in different systems, because that's really the first step toward designing a remediation or prevention strategy to improve the quality of our environment. A second topic I'm excited to talk to you about is how researchers at Nebraska and in other locations are reconnecting our environmental infrastructure with helping our public health decision makers make better health decisions for all of us. So the background slide here is a map that John Snow actually created of London in the late 1800s. And this was a map showing locations of cholera deaths in the city of London corresponding with pump handles. This is a very famous map, and from this map he was able to deduce that one particular pump handle on Broad Street in this neighborhood of London was actually contaminated with cholera. And when people came to pump water, they were getting cholera and infecting their households. And so we had a really strong connection between environmental infrastructure and health in the 1800s, but over time, that relationship has kind of diminished. But lately with the COVID pandemic, it really brought forward this idea again, and it's been reimagined with terms what we call wastewater-based epidemiology. So the idea here for us as engineers who design and utilize infrastructure for our wastewater is we can collect information, collect samples from our existing wastewater infrastructure that gives us information about a community's health. So we can take a wastewater sample from our sewer system and it can contain chemical or biological information that gives us information on different types of things, levels of viruses, the amount of illicit drugs that may be used in a community, antimicrobial resistance, emerging infections or toxins, and this doesn't require individuals to go to a hospital or be tested. It's just information that we can gather from these environmental samples. We found that wastewater-based epidemiology can really complement other types of health monitoring. And again, I think we all became familiar with this through the pandemic. With the COVID pandemic, there were drive-through testing centers where people would take COVID tests, but as we saw that as the pandemic declined, we stopped doing that type of testing, even though COVID is still circulating in our community. So we can use this wastewater testing. It provides a different type of information. When an individual goes to a testing center, they get a test for them, one person. A community wastewater sample gives you information on what's happening from a large number of people, all of the people that are contributing to that sample. So it's not a replacement for different types of testing if we would have a different type of pandemic, but it provides new information that at a community level can give us information on what's happening with health within that community. So at the beginning of the COVID pandemic, we were really fortunate to gain some funding from the university and from other sources that allowed us to start implementing this technique in Nebraska and on the UNL campus. And what that led to was with support from the Department of Health and Human Services development of the Nebraska Wastewater Surveillance System. So with colleagues at UNMC and the Department of Health and Human Services, I've been involved now over the past few years with this surveillance program. We have wastewater at different sampling locations across the state of Nebraska. Where we're sampling wastewater twice a week, every week to look for certain markers, initially focused on the SARS-CoV-2 virus, the virus responsible for COVID. We're very happy. Many of these wastewater programs are very focused in urban areas. We are really happy that our program covers about 70% of the population of Nebraska and includes wastewater sites in Western Nebraska as well as in the eastern portion of the state. And in collaboration with the Department of Health and Human Services, we are trying to do as close to real-time reporting as we can where this data is reported out within the week of sample collection. So these are just some of the examples of what these data look like. This is statewide data showing you weekly concentrations of wastewater at various sites across the state. And you can see the fluctuation in those COVID levels. And this type of data goes to public health decision makers. It goes to the public health districts across the state and other users of the data who can then incorporate it into their decision-making process. We also find interestingly that our wastewater data really tracks with hospitalization data across the state. So this is a figure that shows the gray shading is the COVID level, the blue line are hospitalizations. And so you can see periods where we have elevated hospitalizations. Also we kind of see peaks in that COVID data as well. It's not always exactly the same. We're still working out why we might see some differences between hospitalizations and wastewater COVID levels, but we are seeing that there are connections. And this has been very helpful for entities when they're trying to plan, especially during the height of the pandemic, when they were trying to plan for COVID searching. They were using this type of information to help make decisions on how to manage hospital resources. The data is also reported out to wastewater treatment plants and reported to the Centers for Disease Control as well. So we're very happy about all of that data coming out from the state of Nebraska. And we can also provide different metrics to locations just showing if their COVID levels are decreasing or increasing relative to the prior weeks. And then just want to also point out that our trends are not the same all over the state. And so this is why it's really important to have monitoring at different locations around the state. This figure just shows that COVID concentration trend for our individual locations over time. And you can see it's not always consistent, right? Some areas are decreasing, others are increasing, and this is why it's important not to just do this in Omaha or Lincoln, but to have these locations across the state of Nebraska. We also have the ability with our collaborators at UNMC and the Nebraska Public Health Lab to look at COVID variants. And so again, we've kind of gotten away from some aspects of the COVID pandemic, but for a while we were very concerned about the new variants that were coming up, what types of potential new symptoms or their transmissibility. And so we have the ability not just to detect the amount of the virus, but also to sequence that virus and to detect new types of variants that may be coming up in the community. And so again, this just provides information to allow our health first responders to make better decisions about what might be coming for the future. And while we know that the COVID pandemic is hopefully in our rear window, this program is now expanding to include other kinds of health markers. So most recently they've been monitoring the same wastewater samples for RSV and also for influenza A and B, which we know cause a lot of issues with elderly, with children. And so now we have this new tool in the state of Nebraska that allows us to look at these levels at a community level and hopefully make some better decisions about how we can manage these other types of illnesses that we know affect us on a yearly basis. So again, my takeaway message from this second part of my talk is really that we have this wonderful engineering infrastructure in place in all of our communities, our sewer systems, which usually we think of as kind of out of sight, out of mind, we don't often think about what's happening in those pipes that are running underneath our feet. But our engineers can collaborate with our public health practitioners and utilize information that's in our wastewater, hopefully to improve our community health. So I have a number of people that I'd like to thank. First, I have had the great fortune of being funded by a number of different agencies with some of the work that's presented here. So funding from the National Science Foundation, the Department of Agriculture, the Nebraska Department of Energy and Environment, and the Nebraska Department of Health and Human Services. I also have to thank many former and current students and postdocs who have been very helpful and have really done a lot of the work that I'm presenting today. I also have a lot of wonderful colleagues at the University of Nebraska as well as the University of Nebraska Medical Center who have just been very instrumental in collecting all of this data. I also have to give thanks to the Nebraska Center for Materials and Nanoscience for some of the instrumentation that allows us to measure some of the plastics that we're finding in our environmental samples. And I also just want to quickly put up information about my lab, the Environmental Quality and Communities Lab, really focused on the intersection, as you can see from this talk, of environmental contaminants and how that can lead to information that can help us protect our health. I'm interested in contaminants that affect Nebraska communities and you can find more information at my website. Thank you very much. Thank you, Shannon, for that very thought-provoking lecture. We're so proud to have you as a national leader in this space and your leadership is evidenced by your recent election as a fellow of the American Society for Civil Engineers. So congratulations for that. We now have some time for questions. So audience members, please note on your screens how to submit questions and we have a few questions that have already come in, so let's get to those. Sounds great. Shannon, what are some of the challenges of identifying new or emerging environmental contaminants? That's a really great question, Sherry. So I think one of the challenges is first we have to kind of look ahead to what types of new compounds, what types of new things are being used. So a lot of times as environmental engineers we're looking for contaminants that come from different human uses, different uses in industry or agriculture. So first we kind of have to look forward. People are always developing new technologies. We have to think about what the environmental consequence would be and then we also have to work really closely with chemists and microbiologists to come up with the detection methods. So many of these things like antibiotics have been in our water for very long times but until the development of some analytical techniques to allow us to detect them, we weren't actually able to find them. So I think those are some of our challenges is the detection techniques, but then also having that forward thinking about what types of things we should be looking for next. Yeah, so that kind of ties into our next question which is a question about how long is something like SARS-CoV-2 detectable in water? Oh, that's a really great question. So we do know that the virus can degrade and so viruses do degrade in the environment. Different viruses have different residence times or different half-lives in the environment. There's a lot of research actually going into looking at how temperature, how different factors can affect the virus in wastewater so we can better interpret the information we're getting from wastewater-based epidemiology but we do find that it's stable enough that we can detect it in the wastewater system which allows us to provide that health information. And connecting to the health information, is there a consistent lapse between detecting these elements in the water and relative spikes in hospitalization? Can you talk a little bit about that? Yeah, actually that is one of the things that was really interesting. It seems that the detection of virus in the wastewater is a little bit ahead of detecting it in infections or hospitalizations. So some of the data that we have is that when we detect the virus in wastewater then we'll often see a subsequent increase in hospitalization so there's a little bit of predictive value. So we see it in wastewater first and then we might see an effect with hospitalizations. We're still trying to understand exactly how those are linked. There's a lot of work going into that but that's one of the hopes that we have is it is actually predictive so it gives people some time to make some changes or react to the data. And you mentioned about this information being provided to public health professionals. So if you were to report some spike in detectable contaminants in the water how might a public health professional use that information? Yeah, I think that's something we're all still kind of trying to work out but we are providing it to the public health decision makers and I think it's gonna use a couple of different ways. They're definitely looking at the information if they see spikes in wastewater and it just gives them information about what's going on in the community and also during the pandemic we were able to work with Nebraska Medicine. They were trying to decide how to make decisions about staffing for hospital beds and they were actually using the wastewater data as part of that decision making process which was really exciting. Yeah, that's great. You mentioned something about the wastewater based epidemiology in one of your previous responses. Can you talk a little bit about what obstacles there are to increase use of this approach? Yeah, so I think definitely we need to figure out really how to make the information really actionable so we can detect levels of different things in our wastewater but it's a new type of information so just as you asked before we have to work with people who make public health decisions to figure out how to make that really actionable data so that's one challenge and then also just we can quantify things but just trying to link that back to actual like we said hospitalizations or cases in the community I think there's still quite a bit of work there that we need to do as well. Great, we're gonna shift gears a little bit to the microplastics. Do you see microplastics and antibiotics being considered for water and wastewater regulation by the EPA or states in the future? Yeah, I think that's a really good question. I think that microplastics are probably farther away from any type of regulation because it's really just been in the last few years that we've been detecting them regularly in the environment. I think some antibiotics, yes, may be a little closer to development of regulation but certainly we've seen with a different compound which I didn't talk about, PFAS that there are new candidate regulations and so yes, I do think probably in the future with more information some of these compounds will be regulated. Great, I hope your lab will be part of those conversations related to new policies. You referenced finding antibiotics downstream of wastewater facilities. We're not designed to remove them. What steps could be taken to update those facilities for better removal of these compounds? Yeah, and there definitely are technologies and techniques that can remove these compounds. Some of those techniques are enhanced filtration or chemical oxidation. Those are very expensive to retrofit at wastewater plants and really oftentimes the wastewater treatment that is in place is designed to remove more conventional types of contaminants, nutrients and bacteria so we can't fault the plants. We've been excreting these compounds for long periods of time but we just know that they're moving into our environment and then we wanna look at what some of those implications might be from that. And if some of those compounds technically could not be removed at the wastewater treatment plant there might be things we could do as you mentioned in terms of monitoring and then what we might do behaviorally with communities for example or something like that. And there's also environmental degradation processes as well. So once something's in the environment it's exposed to sunlight, it's exposed to bacteria so we also see decay of those things in the environment as well. Nice. What opportunities are there for environmental engineers to address Nebraska's environmental challenges? Well I think there's great opportunities. I love being an environmental engineer and I really like working on challenges of infrastructure and how that relates to public health. So I think there's more connection that we can do just showing how our infrastructure connects with health whether that's our drinking water infrastructure or wastewater infrastructure, solid waste how we manage all of our wastes. It's not always very exciting or something that you see on a daily basis but environmental engineers are the ones that are designing all of that infrastructure. So I think just further connecting that with the impacts on health and how we can design the infrastructure to improve health is really exciting. Great, this question might be a little more technical around some of the data you showed but there seem to be a seasonal variation in some of the contaminants that you were measuring. Can you talk a little bit about that? Sure, yeah. So when we measure the contaminants at or near wastewater sites there is a disinfection season and we see higher levels when the wastewater is not being disinfected. So that's one seasonal impact. So when we use chlorine to disinfect it also degrades those contaminants. In the environment those contaminants are coming from runoff activities, precipitation. So often we see higher levels after we've seen rainfall events or in periods of the year when we have more rain because that rain is carrying those contaminants into the water. Very interesting. Does the amount of microplastics change with composting of manure? That's a really great question. It's actually not something we've looked into. My guess is that composting would probably not necessarily remove microplastics in some ways because you heat up the material during composting. It's possible you could actually generate if you had larger pieces of plastic you could actually generate that into smaller pieces of plastic. So, but I don't know if I've seen a lot of studies on what effect composting has. Interesting. Are there any ways to degrade the microplastics in the environment before they get into the water? Yeah, that's a great question. I think that's one of the challenges is we find these plastics but then we have to think about what do we do? What can we do about it? And plastics are so ubiquitous. They're just everywhere. We all use them. And also they were designed to be very long lasting. So then that kind of works against us when we find them in the environment. I think that if we redesign, I think there's some exciting research where people are looking at new bio-based materials. So if we just make plastics from different types of materials that are maybe more degradable or more easily broken down then we would see less environmental plastics. Interesting. Maybe you could talk a little bit about what's next in your laboratory. Oh, that's a great question. Yeah, so we're continuing our work on microplastics. So we're also interested in looking at microplastics in surface water. So similar to the study I presented on antibiotics, we're just interested in how microplastics might move in surface water since we showed that they could be carried in runoff. So that's kind of one of the next steps. We're also interested in looking at how plastics might impact nutrient cycling. So can those plastics interact with bacteria or interact with plant roots that are responsible for how nutrients move in soil and in water? On the wastewater epidemiology side, we're looking now at expanding our network to including more individual facilities. So most of our sites have been community sites but we've actually just brought online some sites at nursing homes because then that's been a location that is of a lot of interest for people related to public health. So kind of exciting to just think about monitoring at a building level as opposed to a community level. Fascinating. And could you tell us a little bit about how students are engaged with your work? Oh, absolutely, yeah. So all of this work was done by and with students. So wonderful group of graduate students pursuing master's and doctoral degrees in civil and environmental engineering and also a lot of undergraduate students. So I've been really fortunate to work with UNL undergraduate students as well as our department hosts a summer research program where students come from across the country. They get exposed to Nebraska and then they get opportunities to go out into the field, out into the water and work on all these projects. And I can tell you're very passionate about this work. Is there a part that's your favorite part of research? Oh, wow. You know, I think my favorite part of research is when students have a really cool discovery or have success in experiments and then just getting to share that with them, honestly, is one of the most exciting things. That's wonderful. Well, thank you again, Shannon, for sharing your research with us and in this Nebraska lecture. And thank you to all of you who have watched today and have submitted questions.