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Think Science: Geoscience & Groundwater

In South Texas, water is a precious resource, and it's closely tied with the ground under our feet.

In this Think Science program held on Nov. 16, 2023, you'll learn about groundwater contamination, storm runoff, the health of area aquifers, and energy production. How does taking care of the surface affect what lies below?

TPR's Nathan Cone moderates the panel featuring researchers from Trinity University and the University of Texas at San Antonio.


  • Benjamin Surpless, Ph.D., Trinity University
  • Brady Ziegler, Ph.D., Trinity University
  • Saugata Datta, Ph.D., UTSA

Use the audio player at the top of this page to listen to the presentation and follow along using the slides embedded below. At the bottom of this page is a transcript of the audio (unedited, may contain some grammatical or spelling errors).

This Think Science event is made possible by Culligan Water and San Antonio Water System.


Nathan Cone [00:00:00] Good evening and howdy, everybody. Thank you very much for being here. Thanks for your support of Texas Public Radio. Welcome to Think Science. I'm Nathan Cone. And our goal at each one of these programs is to get you in and out of the session in about an hour, having learned a little bit more about the topic at hand. And this evening, we're thankful to partner with our colleagues from UTSA and Trinity University here to present to you a discussion about how the way we treat the surface affects what lies below. We have three special guests here that will share some of their research, and then we'll open a question and answer session that'll include you. And you'll notice that we have a microphone available that's over there. Will we be moving it up front when it's time for the Q&A so that when you have a question, if you would, please come up to the microphone. And the reason why is because we're recording the audio tonight so that we can post it online later on our website along with the slide presentation that you'll see this evening as well that will be posted online as well so that you can share it with a friend or colleague or some of the students, you know, that may be interested in learning more about this. TBR wants to offer some special thanks this evening to our Think Science sponsors, Culligan Water and San Antonio Water System. They're making it possible for us to bring you think science and we truly appreciate their good corporate support and stewardship. Thank you so much for being good citizens. And tonight, you're going to learn about geothermal energy production, about the health of our underground aquifers, groundwater contamination, and what these institutions are doing with their students to study and address issues for future generations of Texans and beyond. We have Dr. Ben Surpless, Dr. Brady Ziegler and Dr. Saugata Datta from Trinity University and UTSA. And we'll begin, I believe, at the beginning with Dr. Ben Surpless, who's a professor of geosciences at Trinity, where he teaches courses in structural geology, earth surface processes, global climate change and Earth's environmental systems. Ben involved students in his research in western Nevada, western Texas and southern Utah, where he investigates the geologic evolution of faults, fault systems and fracture networks. So welcome. Thank you so much for being here.

Ben Surpless [00:02:20] Thank you. All right. Thank you so much for that introduction, Nathan. So today, Brady, Saugata and I are going to attack groundwater from different perspectives. I'm a structural geologist, and the two of them are hydrologists. So you're going to see a little bit of a difference in the way that we address groundwater resources. As a structural geologist, I don't know if people even know what that means. I'm interested in things like the way that mountains form, and so early in my career, that is what I focused on. I focused on what are the big fault systems that underlie mountains and cause them to grow through time and how do they evolve? But importantly, since that time, I have thought more about what About the faults themselves. Like not worrying about the mountains, but what about the faults as they evolve through time? The important thing is that as faults form, fractures form around them and those fractures let fluids flow. And so geothermal energy is the first thing that I am going to spend a little bit of time talking about. After I talk about faulting. And then I'm going to bridge to groundwater and that'll just be at the very end because I'm not really a hydrologist, so I'm going to pass that off to Brady. But I should point out that the research that I'm presenting today is supported by the National Science Foundation and Trinity. So when we talk about faults and why they actually form, I mean, you think about the crust of the earth and it's relatively intact a lot of the time, but if the stresses are right, the forces are right, then you actually generate fractures within within the earth. And the important thing about that is that faults start as small imperfections, fractures and grow over time. If you took an introductory geology course or if you have somebody that you know that is in seventh grade right now taking earth science, which I think that's when they hit it. In Texas, the faults exist. They just are. But I think about how did they get to the point that you can identify them as a fault. And so you'll have to bear with me with this analogy, and I use this in my classes when thinking about the way that a fault starts. In reality, it's just a really small imperfection in the crust. And I use pieces of cheese. So at your next barbecue, you can try this and see if you impress anyone thinking of that cheese as a layer within the earth or just a rock layer. And you if you take your left hand and your right hand and then you start to tear it before you put it on the burger. If you start to tear it, you will see that fracture propagating across the cheese. And it turns out that faults don't instantaneously break through the entire layer. They also have to propagate through that slice of cheese. And what you'll notice is that as you're tearing it, the edge of the cheese has moved much further apart than where the tip of that terrace. And so if you think about that with faults, it's it's actually really not that different. Well, I mean, it's pretty different. But but if you think about the damage that actually takes place and that's what I focus on. So as a fault forms in that that fault propagates through time. The damage zone around it evolves with the fault. And so what you'll end up having is this wide zone of damage around the primary fault. Now the important thing is that if you zoom in and look really closely and here we're pretending like we can go down into the earth to do this, there is the main fault core where the two bodies of rock are in contact with each other sliding past. Then you have the inner damage zone where there's intense fracturing and outer damage zone where it's a little bit less intense, and then eventually you get back to the intact rock. But the important thing is that because you have set up this envelope of fracturing around the fault, you increase the permeability and you let groundwater flow. If you're thinking about, well, how do we how do we actually know this? What's important to remember is that millions of years go by after these, you know, as these faults have been active. So erosion takes place. And so much of what we know about these processes is actually based on field data. So I go out with my students to West Texas, to southern Utah and to western Nevada and look at how these faults and fractures evolve together. And the important thing is that when we start thinking about this in terms of geothermal energy, the big faults are the ones that you really start to think about. So if you look at geothermal energy potential across the U.S., it's primarily the Western U.S. where the most potential is. There are areas in Texas as well. But if you want to go to where the big faults are, you usually go west. And so I went to Utah for that reason. And what's what's important is that if you go to Utah and if you've been to any mountainous area in. The West, you know that there's significant topography. It's actually pretty tough to get up onto the mountains and make the observations that you need in order to create a predictive model. And especially that's especially the case when you have a 100 meter, 200 meter, 300 meter cliffs where the fractures are amazingly well exposed. But unless you decide to repel down the side, which people literally people did say that's what I should do in order to get the data. Turns out drones are much better. Much, much, much better. And so for both, for about the past ten years, the drone technology has improved so much that that's what I do. I go out and I do do collect field data, but then I also fly basically pan across these spectacularly fractured rocks that are and this is about 200m off the ground. If you think about the fact that you can capture all of this, you know now how those fractures are related to each other, their geometries. But what you can't do with the drone imagery alone is actually measure things. And so we need to create a computer model to do that. So the probably the best way to think about this is our eyes are two cameras and we have an image that's captured by each one of our eyes. And so if you think about any object, you can figure out which direction it is relative to you and about how far away it is from you, because your brain is able to take those two images and give you that information. Now, if you have a computer program that can do it and in your eyes, do this way better than any computer program. But if you have multiple points, then you can start to match those points. So in your mind, is doing that for you all the time. If you do that with this drone imagery and pull out images from all of these images and not just two, three, four, this is hundreds of images of a landscape. You can create what's called a point cloud. And that point cloud is spread out across the landscape. And once you have the landscape points, then you can connect to them and eventually you can create a landscape on a computer that matches exactly the landscape that you see and hear. And for those of you who are listening, you can't see what I just referred to. I promised myself I wouldn't say, as you can see here. But what you can then do is overlay the original imagery over that three dimensional imagery. And so you can get as close as you want. And if you geo reference it, you basically pick points that are exactly located on Earth. Then you can directly measure things and quantify all of the deformation that you see. Now, if you start thinking about how you can use this, once we document this well enough, then you can actually project this down into the subsurface and use it to make predictions about geothermal energy. Now I'm going to bridge briefly in groundwater flow because I want to point out how important faults are to the to the Edwards Aquifer system. So I'm going to do this fairly quickly because I know that Brady is going to spend more time in groundwater. But I wanted to point out that if you're in San Antonio and you think about the Hill country, that's up to the north, that is where when you think about the rainfall that comes down in the hill country, the Edwards group is up there. And so it's porous and permeable rock. So some of the water goes into the subsurface, some of it flows over the surface. That water in that contributing zone to the aquifer flows to the south. And that's where the balcony fault zone is. The recharge zone is there because you have a huge number of significant faults that have fractured the rock around them and created these pathways for the water to enter the subsurface. And if you think about what I mentioned, the Edwards group that is way up in the hills, that same Edwards group is the one that is down below our feet here in San Antonio because the faults have dropped it. So as you move to the south, the same unit is now way below our feet, hundreds of feet below us. And so when we think about the way that water is flowing through the whole system into the Artesian zone beneath San Antonio, it's there because of the faults. If we didn't have the balconies faults and we would not have the resource that we do today. And with that, I'll pass it off to Brady.

Nathan Cone [00:11:59] Yes, as a matter as a quick introduction, Dr. Brady Ziegler is an assistant professor at Trinity University whose research specialty is in biogeochemistry. He uses principles of hydrate, geology, geochemistry and microbiology to evaluate the behavior of contaminants in the environment with the aim of protecting drinking water quality. Thank you for being here.

Brady Ziegler [00:12:30] All right. Hi, everybody. Thank you so much for having us here tonight. When I think of groundwater, I think of three big questions. The first being how much is there? The second, how good is it? And the third, where does it go? Which is especially important if your water is contaminated. Now, I'm going to spend most of my time talking about that second question of how good is it and how water might get contaminated. So my goal is to maybe help you think about groundwater contamination in ways that you haven't before. And to start off, the way that water can often get contaminated is through aquifer recharge. So depending upon what type of aquifer you have, the zone that can contribute to contamination can widely vary. So on the top, we've got an unconfined aquifer. And what defines an uncommon unconfined aquifer is its ability to interact with the surface. So any surface contaminants that might get spilled accidentally could potentially make their way down into the water table and contaminate your drinking water source. A confined aquifer is separated from the land surface by this impermeable material that overlays it called a confining unit. Oftentimes we think of clays and salts as confining units. So from a surface contamination standpoint, the only way that a contaminant can get into a confined aquifer is through its often fairly narrow recharge zone. So you might look at this and think, okay, probably unconfined aquifers are more vulnerable to contamination than confined aquifers. And to an extent that that is true. However, it's not the full story. So here we're looking at an image from the U.S. Geological Survey where they looked at various different types of contaminants. And what we see is that some types of contaminants almost exclusively only contaminate unconfined aquifers, nitrates, volatile organic compounds, pesticides. However, there are other things like trace metals. And radionuclides, which can contaminate confined aquifers to a very severe extent. So trace metals contaminate unconfined and confined aquifers in equal proportions. Radionuclide to actually contaminate confined alcohol is more than unconfined aquifers. So the question is, is why this distinction? Well, that first group was primarily contaminants that originate from manmade sources. So things that are getting introduced into the ground at surface level, these others, trace elements and radionuclides have natural sources. In other words, they exist in the rocks and in the minerals that make up the aquifer itself. So just because it is confined doesn't mean that it's necessarily protected from these particular types of contaminants. So maybe when you think of contaminants, you've often thought of humans or as contaminants by and large. So. Chemical spills, landfills. We introduce bacteria accidentally, often pee fast as a big one. That's being talked about right now, often referred to as forever chemicals, often used and for their nonstick properties. Chemicals of emerging concern like pharmaceuticals, personal care products, fertilizers. These are kind of our classic contaminants. However, I would like you to kind of consider geologic contaminants as well. There are lots of different minerals that contain a lot of different trace metals that can potentially serve as a source of contamination. So uranium, mercury, lead, cadmium, arsenic, all things that are very toxic, all things that naturally exist in rocks and minerals. Now, where I like to spend my time in research is thinking about the intersection of these two different realms. So, for example, I do a research project looking at how nitrates from agricultural fertilizers can actually interact with the mineral urine tonight, which is a uranium bearing mineral. And through that reaction can actually dissolve uranium into groundwater. In another project, I'm looking at petroleum hydrocarbons and how those can interact with iron oxide minerals and release iron into groundwater. Now, an interesting thing about iron oxides is that they can generate a lot of surface charge, meaning things stick to their surface. But if the minerals dissolving, those things stuck to it are also dissolving. So arsenic often associates with iron oxides and can be dissolved when you introduce some sort of chemical contaminant. So in that vein, I wanted to show you kind of just how frequently we accidentally spill things on the surface of the Earth. So these are data from the Pipeline Hazardous Materials Safety Administration. And what we're looking at is pipeline releases. We average over one pipeline spill per day in this country. And you can see they are concentrated in some areas in particular that are important to us. If you look at West Texas, out in the Permian Basin, where we have a lot of oil development, we have a lot of pipeline spills. If you look kind of down where our major refineries are in the Houston Galveston area, kind of all pipelines lead down to Texas. We have major concentrations of spills that occur right here. So one thing I want to point out is each of these places where you've got these petroleum releases, not only do you potentially have a petroleum problem, you could potentially have an arsenic problem and not even necessarily know about it, because historically we haven't really considered those two things linked together. So for those of us who are interested in protecting groundwater resources, we've got our work cut out for us. This study, it was put together by the National Water Quality Assessment Program through the US Geological Survey, where they looked at all of the major aquifer systems throughout the United States and basically quantified how many wells in that region are safe, maybe in danger of being contaminated or are certainly contaminated. So, you know, there's a lot to look at here, but we could focus on the Edwards Trinity system. About 51% of the wells that they sampled in that region were safe with respect to all contaminants that they measured, which is good. However, about 16% exceeded some safety threshold for at least one contaminant. And then the remaining third was above half of our respective threshold for at least one contaminant. If we look elsewhere, some places do a little bit better. So the Texas coastal uplands, 83% of their wells were safe with respect to all contaminants. Good news as we move north. Kind of where I'm from in the Cambrian Ordovician aquifer system, over 50% of the samples were bad. They were unsafe. So kind of what degree of safety you have kind of depends what anchor river system you're pulling your water from. Now when I'm talking about safety. The question is as kind of what do we mean by that? So the EPA regulates about 90 different chemicals with their national primary drinking water standards. So the goal here is to protect human health based off of toxicity studies. If you are interested in looking at that website with the various chemicals, you can scan this QR code and you can look at the full list. So here's an example of things that you might see. Antimony, arsenic, asbestos, atrazine. So we're just kind of in the A's and the bees here. The safety thresholds that I've been mentioning are what are called these chemicals stands for maximum contaminant limit. So, for example, if we look at arsenic, the maximum maximum contaminant limit is 0.01mg/l, meaning if my water exceeds that concentration, it is unsafe with respect to arsenic. And you could have skin damage, increased risk of cancer development, and a whole host of other health effects. Now, one thing I want to point out is just because we have these 90 chemicals regulated at the federal level doesn't necessarily mean those are the only things we need to consider when we're thinking about safety. Right. Other different chemicals can potentially contribute some toxic effects. So the EPA has what's called this contaminant candidate list where they're considering other chemicals to add to this because of known health effects that they can cause. So getting a little bit closer to home, thinking about our aquifer systems. We've got nine major aquifers throughout the state of Texas. We could spend a lot of time looking here, but we're going to focus primarily on the Ogallala Aquifer in northern Texas. We're going to look at the Gulf Coast, Texas along the along the Gulf of Mexico, and then we'll look really close to home at the Edwards system. The Ogallala and the Gulf Coast Aquifer are those unconfined aquifers that can interact directly with the surface. And then the Edwards in the blue here has a recharge zone that is the unconfined portion. And then kind of hashed here is the confined portion of the Edwards aquifer. So the Texas Development Water Board has put together a really nice report looking at the various different chemicals in groundwater in the state of Texas. So if you want to access that report, I've provided a QR code that you can scan here. And I'm just going to focus on a couple of these, but there's dozens in the actual report. So because I study arsenic, I thought that would be an interesting one to talk about. So what we're looking at here is a map. And each dot represents a well that was sampled. And anything that is in the red or the black color is unsafe with respect to arsenic. And you can see that arsenic is not widespread, equally and equally distributed across the state of Texas, there are little hotspots. So if we look primarily in the north and the west, there's a lot of wells that were unsafe with respect to arsenic. If we look further toward the south along the Gulf Coast, pretty widespread elevated concentrations of arsenic. Good to note here in Bear County that we've highlighted here in red. We don't have especially high arsenic, so that's good news. So why kind of this uneven distribution? Well, when you take a look at where these different hot spots are occurring, they tend to be pretty dominated within the Ogallala Aquifer system and in the Gulf Coast aquifer system. So this is telling me is that there must be arsenic bearing minerals in those aquifers. And the chemistry exists such that those arsenic minerals are releasing it into groundwater. Elsewhere. We probably don't have quite so much arsenic or we don't have the chemical recipe necessary to release arsenic into groundwater. Next it looking at uranium data is a little bit more sparse. Not quite as many dots, but we still do kind of have these zones where we've got some increased uranium. So one of the things that we need to think about here is why. Well, remember on about the second slide I had mentioned, uranium can interact with agricultural nitrates if we apply fertilizer to the ground. So one of the things that we could do is say, okay, here's our regions of elevated uranium. What does nitrate look like? So keep this image in your mind. And here's our elevated nitrate concentrations. So these are examples of where nitrate is being applied to the land surface. It is leaching down through that unconfined aquifer system and it is interacting with the natural uranium in the sediments, and it is releasing that uranium through a chemical reaction. So you might also notice there's regions where there is elevated nitrate, but there isn't any uranium. Why is that? Probably there's very little uranium actually in those sediments. So you can add nitrate, but there's no uranium to react with in those particular rocks and minerals. So it looks like the Ogallala and perhaps down in the Gulf Coast, we do have uranium that could potentially be released into groundwater through nitrate application. So thinking about groundwater contaminants, I tried to boil down what we just talked about into a nice little grid. So if I'm thinking about human source contaminants, there are some questions that I want to ask myself. Are chemicals being applied to the surface environment? If I'm in a confined system, I want to ask myself that same question, but then I want to think, is it occurring specifically over the recharge zone? If it's not, that aquifer is probably okay because of that confining layer that lays over the top of it. For geologic contaminants doesn't really matter what's going on at the surface necessarily. We need to wonder, are there minerals in this particular aquifer that could be released due to reacting with due to reactions with natural groundwater chemistry? Or are humans modifying the environment in some way that could cause those elements to be released into groundwater? So if you're interested in checking your water quality status, if you're on a municipal level, remember that it's the municipality's responsibility to keep groundwater quality within regulations so you can access the source groundwater quality report through this QR code. There's another group called the Environmental Working Group that does its own separate report, and you can see that their assessment is that tap water provided by this utility being source was in compliance with federal health based drinking water standards. So we do have pretty good water here in San Antonio, which is good to know. They do point out that there are some contaminants that they detected. These are human sourced contaminants. They set different standards than what EPA sets. So they say that they exceed what they consider safe and not what EPA considers safe. So there are things to look out for. But overall, water quality in San Antonio is pretty good. And then if you're on a private well, an important thing to know is that it is your responsibility to monitor and check your water quality. If you don't monitor, you don't know what's there. So the Water Development Board for the state of Texas has a good set of recommendations that you could potentially access and learn. What should I be looking for and who should I contact in order to have my well tested? Thank you.

Nathan Cone [00:26:59] Thank you so much, Dr. Ziegler. And finally, as part of our trio here, we have Dr. Saugata Datta, who's a professor of chemical hydro geology and aqueous geochemistry at UTSA. And his research interests focus on issues of water resources, water availability and an understanding the cycling of different metals and organic compounds in our groundwater, surface water, soils and sediments, as well as how land use pattern changes affect the distribution of such metals and pollutants in our environments. Thank you so much for your time and for being here.

Saugata Datta [00:27:31] Thank you very much and good evening, everyone. It's my pleasure to be here. I like to just start by saying that this is a collaborative work with many federal agencies that we work with in terms of sponsorship, like National Science Foundation, Geological Society of America. And, you know, after coming to Texas in 2019, I did realize that [we have] one of the one of the safest and one of the cleanest aquifers that we are sitting on. So we are pretty good in that sense. But still, we need to look out at, as Dr. Ziegler just said. So just to look out for Texas, and this is a kind of a nationwide study that was done for the last few years, actually, that was taken from many of the aspects of where and the different contaminants that we are talking about. And, you know, you heard about nitrates, you heard about arsenic, you heard about copper and lead. I will talk a little bit more about that. And then, you know, the disinfectant, byproducts, radionuclides, these are also very common ones that probably are in case of the disinfectant byproduct is are more anthropogenic. And then some of the other ones which are on the list are more geo genic are natural. Right. So we we need to kind of differentiate between these right away when we are talking about contamination in drinking water is one of the things to talk to kind of understand here is that in a lot of the other ones that we do not sometimes take care of are the total coliform are organic or equally contamination in many of our drinking waters. So in this in this study, actually, this nationwide study that was done until 2015, as you can see, there's a quite a high number of violations of the community water system and the water quality violation in Texas, like in other other other places in the nation, too. And this is a statistical method that was used to spatial clusters rather, you know, in this case what we call as the hotspots of health based violations from the standard or the drinking water quality or the act that has actually had it for a long period of time. And that's what we are promoting, that, you know, our water quality should be below those standards, meaning that it should be like, you know, below the seal. So the maximum contaminant limits. But note that there are some hotspots of some of these are in Texas also. So with this in mind, you might have heard about a very common one in the last few years is lead and lead in drinking water. That's one aspect of it. But again, you have learned about Flint, Michigan, where major, you know, led outbreak from the infrastructure pipes, the iron pipes that was lead that was very high in lead that actually got into the water and in a very high concentration late is not carcinogenic. You heard about arsenic. Arsenic is cancer causing or carcinogenic. A class one carcinogen lead is not. But lead has other very, very derogatory effects on human bodies, especially children. One of our studies in Kansas, when I was to be there before 2019, we did with the Children's Mercy Hospital in Kansas City area in the tri state mining district, to look at children with lead level in their blood, more than five micrograms per deciliter. So just a very minimal amount. And what we did was a very state of the art work to look at some of the stable isotopes of lead geochemistry, to see what the concentrations of this lead are or where the source of this led are. And the sources of lead can be from not just water but from inside house dust, soil paint and household objects. So we have to kind of look into that aspect to one of the common ones that we know, I think are in Texas, in the Harris County near Houston or in Houston. Right. There are quite a few of the reports that has come out with high lead concentrations in their water because of this, you know, very old infrastructure form from lead pipes. And, you know, in one of these aspects of it are very common that we have hard in Flint, Michigan. And so we can draw a lot of conclusions and anecdotes from there for our future studies looking at that. As Dr. Ziegler was mentioning, about some of the other contaminants. And and we are sitting on a safe aquifer system in Edwards Aquifer. But then again, to look into a little bit more closely into those into those contaminants that probably not in the not in the short term, but maybe in the long term as we use more or as we exploit more of our aquifer water, these contaminants can be of immediate issue. And just to point out, some of them in this case are, you know, some of the ones that you just heard about like Chlorides are fluoride or nitrates or iodine or even phosphate to some extent. You know, it's not like a real contaminant, but, you know, it can be from nitrates. And phosphates are very common from agricultural land. So land use pattern changes of these areas that can also negatively impact the groundwater quality in the long run. You heard about lead arsenic and also radon. Like, you know, some of the radionuclides as we were just talking about deaths to keeping track in this case. The recent studies have shown some presence of contaminants of volatile organic carbons or pesticides or herbicides. And these are not uncommon in Texas. The reason because, you know, these are mostly agricultural irrigation based and these are all to the nation. And but whether we are crossing that threshold limit or not is the main question. And to look at very acutely and monitoring the groundwater quality, you know, very frequently is what is needed. And there are many, as I said, in in Houston, there are Led programs that are now being done. And it's very efficient in looking at our checking, at least the the blood lead levels of children. So in our case, we actually paired up with Edwards Aquifer Authority to look at one of their very controlled site. It's called the field Research site r, f, r p site. And what we do here are the control wells where practically these wells can be affected by land use pattern changes or sewage influx or natural contaminants coming into like, you know, any kind of bedrock that is reacting with the water. And it's actually causing more and more of these ions and trace elements or heavy metals to be in the water. So we do a very exhaustive collection of water. We check for many aspects of it. One of the ones that we check for are rare earth elements, and these are rare Earth elements are not notoriously any high in concentration or we have to be cautious about their contamination limit. But we use rare elements as tracers to actually trace some of the known contaminants in the water. So it's like just a dye, right? And these dye concentrations in the water can vary from place to place. So we actually collect them and see that, you know, the known concentration of the known contaminants can be figured out from these relatively benign concentrations too, with the linkages in the geochemistry. So from that, I would just switch a little bit from the Edwards Aquifer to a continuous aquifer rather more to the South Transboundary aquifer. One of our students is actually here who has done the work there in many of the counties in the Texas-Mexico border. And the the one of the things to look at is that of the nine counties that we kind of forced interjected all of them four counties. We had more of the data right now. And by by county, by county, some of these sorry, some of these metals are some of these metals are being plotted to show that. How much of these concentrations are involved? The safe limit, Again, they are not too much above the safe limit, meaning that they are within the safe limit. So we are quite good at this point. But as you know that with the irrigation pumping going on in those regions, for many of the agricultural crops out there that need that water, we need to keep a close eye on those that are multiple of these elements that you heard about today. We actually take into account all of them and check and put a check on them to see that if they are more or less than the m-class. On that limit, on that on that end. You know, one of the ones that do kind of take a little bit more closer peek are arsenic and copper companies. Again, not that tremendously toxic. But if it is in very high concentration, it can become toxic arsenic as as we as you already hard, you know, you have to keep a check on those. And what we did here is that is just taking the Texas water development maps and the water that they have collected samples. We kind of made a time series to show that how these metal concentrations in the waters in the in the borderline in the borderlands actually are varying with time. That can also tell us that is that any particular changes that has happening in you know, in a single year that probably has caused any high increase or not? As you can see, most of them are below the safe water limit. Which is which is which is fine in this case. So with this, I will say that some of these unmonitored private wells in the in the borderline, in the in the borderlands in the nine counties that we have done, actually, this is this is a very community based work working with the people over there, actually calling them up from beforehand, going into their houses, collecting the water, you know, analyzing them in our labs and sending back the data to them. This is exactly what we do in our labs, right? It is more science than propagating the science to the people that really they need to know what their water quality is about. And this is what we have been following for quite a few years now, and we are continuing with that information. With that, I'll just say that, you know, many, many parts of the world I have struggled and in Southeast Asia, we cannot just not mention about what the problem with arsenic in those regions are is much more recursive. It's much more, I would say, you know, it's much more dangerous situations out there than what we face in Texas. So we are we are sitting in a again, we are blessed to have such an aquifer, a cost aquifer of this nature with the safe drinking water quality is very important. But keeping the Beijing population growth in San Antonio, we have to keep a check on many of these water quality parameters that we mentioned this evening. With this, I would just point out that at UTSA we have a water institute called the Institute for Water Research, Sustainability and Policy, which actually takes about 40 researchers and students all across the campus from six different colleges that talks about water and science, water and engineering, water ethics, water, economics, water and health. So aspect of it. So if you have questions, if you have ideas, if you have laboratory work that you have in mind to do with us, we are we are all welcoming all of you to think about how we can protect our resources. Water in this Edwards aquifer and also many other aquifers around us. With this, I would say that there are many water pollution prevention programs. This is a simplest one. But then again, I mean, these are many simple ones that we can do for our day to day life. But I would definitely say education and research is very important for any type of water related problems that we face either in our state or across across the state. Policy and regulations do depend on that. And based on these, I think for the future, we have to really look into the proper usage of water, quantity of the water that we use, and especially in times of litigation and so on. And implementation and enforcement also is important. And then citizen science and social responsibility. I think these are the four most important parts of any water research that we have done in the past. With this, I just conclude my talk and open up for questions. Thank you.

Nathan Cone [00:39:54] Thank you, doctor. That I appreciate that. We have about 18 minutes left here. So of course, there is a microphone over there. And if you have a question, you are welcome to go over there. I'll start off with one right now, if I may, to just I really was Dr. Ziegler, it was really interesting to hear in your presentation, you know, those two, the Venn diagram, basically, of those two of the contaminants that and how what we sometimes put on the land, I guess can they're doing things that we normally the ordinary person would think, oh, that's poison, I don't want to put it out there. But there are things maybe that we're using that are breaking things down and releasing natural contaminants into the soil and water. So as consumers then, you know, because I think if I go to the store, I'm going to go look for the natural stuff, etc., etc.. But what should we be looking for? What are the things that we need to worry about as consumers for taking care of the land and not wanting to release stuff that's already there? You know?

Brady Ziegler [00:41:00] Yeah, that's a good question and a difficult one to answer. I think probably the best bet. Is. If you consider what the actual application guidelines are on that particular product, that's probably the best bet. Oftentimes these issues with, for example, nitrate getting into groundwater that can potentially cause a uranium problem. It's from an over application of nitrate We're putting on more than we actually need. So if we are. Sustainable with our choices of how we want to apply that nitrate. I think oftentimes we'll be okay. The thing is, we get a little greedy and want a little bit too much fertilization, and frankly, the crops or the lawn doesn't necessarily need it. So I think just being judicious with that choice is probably the the best course of action.

Nathan Cone [00:41:50] Be sparing. Be sparing. Okay. And Dr. Darrow, one question for you also that I thought right there was when all these maps are just so fascinating to me. And so when you we pulled up the one of the Safe Water Drinking Act violations, and there's two dots right there around the Permian Basin in Texas, and then there's also some in Oklahoma right there. And we know but, you know, there's an oil production that historically has happened in Oklahoma as well. But there's also oil production happening elsewhere in the country, too. So what's the deal? Is it just that the you know, the regulations here are. Yeah. You know.

Saugata Datta [00:42:24] I think that's. Yeah. Thank you, Nathan. That's a great question. And I think this actually points out that how much aware we are about these type of problems and surely Texas and Oklahoma are pretty up in that up in that letter. And in many of these sense, I will say that when when this national study was done, it was actually concentrated on some of these states like Oklahoma and Texas and some of the oil producing states. And so so it was it was kind of targeted study. And a lot of these targeted studies do find something that probably has a lingering effect at the end, too. But these concentrations that they found and some of the violations that they found, I think they are very you know, for that time period, it was it was very, I would say, proper. But then again, it might dissipate after after that time period, too. So it's a continuous monitoring that needs to be done from from that angle. And I think some of these national studies that are done by USGS, they are doing it. They are actually targeting that. But statewide studies are much more constricted towards the state and doesn't go beyond the state. So we don't have much information that if there is any interaction going on between the other states coming into our state or not even in the water, what is such a thing that these are that we call it like a transboundary aquifer? And this is a classic example of why water can propagate from one place to the other and the contaminants can be brought in from one place to the states may not be an original place where the origin is, rather rather it can be, you know, coming from other places too. So just keep that in mind.

Nathan Cone [00:44:04] Water doesn't care about what the map says water does when it does. Exactly. Yes, sir. Go ahead.

Speaker 5 [00:44:12] Thank you. And thank you for three very interesting presentations. A while back, I was looking at some water quality data from the Edwards Aquifer Authority. And, you know, they sample wells throughout the San Antonio portion of the Edwards Aquifer. And one thing that surprised me was in virtually every well, were they collected samples for PFA s as they found it Now they found it in very low concentrations, nano and pineapple gram per liter. But still it was there. And I wonder if any of you have an idea of why the PFA answers would be found such a wide in virtually all the samples, even in rural areas where you wouldn't expect that kind of thing. Thank you.

Brady Ziegler [00:45:08] Sure. So the I think the nickname of Forever Chemicals is apt for those particular for that particular group. So those chemicals are really, really difficult to break down and have. I think unknown is probably appropriate lifespans in the environment. So once a molecule of P fast gets into the ground, it's going to be there for at least how we characterize things forever. Maybe not on the geologic scale, but from our certainly societal standpoint, it's going to be something that we're going to be dealing with for a long time. We don't really know how to break them down well.

Saugata Datta [00:45:47] I might just add that, you know, these are fluorinated compounds, right? I mean, one of the things about fluorinated compounds are fluoride as such. And these formulated compounds are very dissolvable in water in a very minimal concentration. So a lot of these Air Force bases that we have been seeing that some of this be a phase are actually coming up more. And the groundwater nearby APRs are showing even in, as you mentioned very correctly, like in very minute concentration. But it's still there. We did a walk with one of our one of the industries nearby in San Antonio to look at how to break down these fluorinated compounds. If we can do that in a laboratory scale. Probably we can do that in a much more larger scale in field. And the point is that, yeah, I mean, what happens is that you have to make sure that this new compounds can be calcined. It can be added to cause, you know, calcium based compound and calcium fluoride as and fluorite. That's what calcium chloride is that can precipitate out. And that precipitation tangent is very, very low. It doesn't do that much. So in nature, actually, even if you have a lot of calcium and sodium based compounds in the water, basically they don't react. They they leave those fluorinated compounds kind of intact and that's why they can spread fast or even in places where you don't usually see any source, probable source that can where the [inaudible] will come from. So I think that might just be a little bit more additional to what Brady said.

Nathan Cone [00:47:28] Yes, ma'am. Please go ahead.

Speaker 6 [00:47:31] Yeah. We all know San Antonio is growing rapidly and we know in what directions. In what directions it's tending to grow and growth is being encouraged. I see some conflict between that and where our recharge zones are. Given what you folks know about potential contaminants and what people know about development. Are the people who should be keeping their eyes on these things, working to protect the greater community or the water sources? Or should we be concerned?

Nathan Cone [00:48:15] And how closely maybe do your institutions work and advise perhaps legislators and the people who make those decisions?

Ben Surpless [00:48:25] I like it. I could. Go ahead.

Saugata Datta [00:48:26] Yes. Thank you. Then I can add a little more.

Ben Surpless [00:48:29] Well, I mean, it's a great question. And I think one of the more interesting things is that over I think it's like since 1980, we are still using about the same amount of water relative to what we were back in 1980. So I think that soars. And in general, even as development has accelerated, those managing the water resources themselves have been good about finding ways to be more efficient with what we have. However, the amount of development up north, I mean, I don't know if I'm I'm assuming that's what you were you were thinking about like the development of North is happening so fast. And what's interesting is that the there's an unincorporated incorporated issue there, too. Like what? Who approves development is going to vary depending on where you do that development. So and I know that San Antonio has actually been, I think, fairly aggressive about incorporating as that development moves north, as far as I know. And maybe you two can speak to this better than San Antonio and Sawers and the Greater Sand Aquifer Authority have all been involved in attempting to to make sure that you don't have issues of contamination related to that development and their rules on how development takes place. But I'm not a hydrologist. I just read a lot about it.

Saugata Datta [00:49:52] Well, I can just quickly add that, first of all, it's a great question. And really, this is it. This is what citizen science is all about. You know, this is what we should be aware of, not just propagating the fact that there may be contaminants in the water. What to do with that? As you know, if I'm a homeowner, what how am I supposed to behave myself in everyday life? Absolutely. And so so one of the things that I think I have I'm I startled quite a few states and I think Texas is quite, quite knowledgeable on that. We people are inhabitants are knowledgeable about the water because probably we have one of the safest water in in the in you know at least currently as it stands like. But for the future, I will say that you are absolutely correct with the growing population and the way the land use has been changing through the years, this is one of the reasons why we paired up with Edwards Aquifer Authority to do a more constrictive controlled study where these wells probably have no other impact from nearby locations unless the the the the growing regions that are near these controlled regions are pouring in some of these sewage based waters or some of the agriculture based waters that are coming in. We can get an impact. I mean, we can get a direct impact from them right away when we sample and actually analyze them, not just those for those test models or ions that we just talked about, but for multiple other parameters. And one of the beauties of beauty, of working with water is that this water chemistry is kind of interrelated. You can use one to trace the other. And I think that's that's one of the things because they are interacting so well with with the rocks from or the natural materials, if it is a soil or if it is a sediment or even the bedrock, if they're reacting, those type of stressors can actually take into account if we take them into account, we can trace back and say that this is where it is coming from. One of the reasons why we do isotope studies is basically to trace the sources and, you know, so there are some laboratory based more, I would say, unique and focused work that can be done more to help in these type of questions, but definitely more so can should be done beyond the institutions, the educational institutions that we just you just see in front of you. I think the the Texas Water Development Board, when I first came in 2019, I was I was really surprised that already arsenic was in their in their list of contaminants that are, you know, elements that they need to check for the homeowners like as Brady just said that in private wells when I was in Kansas in the first time I stepped into Kansas in 2008, the arsenic was not one of them. They were actually thinking that probably this is one of the Oglala aquifers. Our aquifer was one of the safest aquifer in terms of arsenic. And then they started finding many, many, many such arsenic based compounds, maybe geo genic or maybe anthropogenic in the water. So again, you know, communication is important and citizen science is very important to promote the legislature to do what it needs to be done.

Nathan Cone [00:53:11] We have time for one more audience question. Go ahead.

Speaker 6 [00:53:13] Hi, my name is Mandy. I'm a military spouse, so I'm a guest in this host state right now. And of course, everywhere we go, water is an issue. It's something I'm always interested in, not just the drinking water, but the local water amounts. And so this summer, we had an unprecedented drought, and it's the hottest I've ever been in my life. But my yard was the driest it's ever been. And I just wanted to know if there are any concerns about the amount of water that was left in the aquifers here in Texas. I saw it daily on the news. I kind of tuned in to see what how much was left. You know, Canyon Lake, they talked a lot about Canyon Lake. And so I just was curious if the amount not just the contamination, which I thought that was an excellent question, but the amount of water just in reference. We've lived in Germany. They had water conservation efforts in place in your everyday life. We were measured on our water runoff, how much storm water we were producing. So we got charged for that. We had green covers on our roofs. We had waste or water cisterns in our backyards for rainwater reuse. Canada charges us based on high usage hours. And I just was curious if Texas is concerned and if they may want to implement some of these things that are more incentive oriented. Thanks.

Ben Surpless [00:54:46] Well, at one point I taught a course where we looked at. I actually had a group of students that had a GIS project and geographic information systems looking at water usage across San Antonio. And there is a very, very, very strong correlation between income and worries. It was astonishing. And in it, if you look month to month to month, it didn't seem to have any impact. It if you looked, for instance at that time, I'm not sure what how the rates are set up now, but at that time they escalated with once you went to higher and higher usage. But for the wealthier people who want that green lawn, they will spend the money to make it happen. So it was clear that it wasn't actually working. I'm I'm not, I think, mainly making you feel any better. But I mean, my our neighbors, like all of our neighbors. And the crazy part was that this summer was interesting because in June, if you remember, we had a ton of rain. So all over our neighborhood, people replanted sod all over their yards and were watering like crazy through July, August, September 2nd in order to keep their lawns going. So I don't think we are doing enough. I don't think. But unfortunately, I don't know that anybody is pushing that hard to to make a change in the way that we manage our water.

Brady Ziegler [00:56:10] And I would even say that current management practices so like water restrictions are not being enforced necessarily all that well. There are a lot of people who are watering on days that are not their water days and they're not getting fined for it. So in terms of the energy to put in stricter regulations, I don't see it there currently, but longer term trends can bring about change. So we'll see kind of what happens. You know, we've had a couple of pretty dry years. We'll see what the future has in store and if that brings about any change at the legislative level.

Saugata Datta [00:56:47] Yeah, I mean, I was intrigued by your question actually, that, you know, you when you compared to Germany, like I was just in summering in Darmstadt and I was looking at their my, you know, how their water quantity and water quality is being promoted by the citizens over there is far more applicable there than what is in U.S.. I can tell you right away they are they are definitely more pragmatic, you know, the pragmatic use of water, because I think the climate change aspect that you pointed out with the drought that has actually affected Texas for the last few years and severely this year. I mean, I was in an Edwards Aquifer summit this few weeks back, and you have heard about probably that some of their wells where way below their, you know, usual yearly contribution. And so that will remain like this for several years down the road. So the future really needs to be tackled in terms of water quantity in a much better way in the state of Texas. Yes. Truly, the Edwards Aquifer has a sustainable future. It's not it's really sustainable. I mean, to say this from our studies, a lot of studies has been done on hydrological modeling. When you do modeling in the subsurface, like we talked about too much about the water quality today, but when we do about what water modeling, we can really see that how the water is actually depreciating at times with the seasons and with time. And I think we that I will say that with that with the results that I have seen so far, it's not that bad as much of like, you know, problematic maybe. But with with population, as you just mentioned, growing up in growing in San Antonio, this also will be a problem in the future if we are not aware of how to deal with this.

Nathan Cone [00:58:43] If I can wrap up with one quick future looking question maybe for you, Dr. Surpless, which I love seeing the students doing this field work at with your class at Trinity. And I, I'd like to ask this of panelists think science from time to time if you have if I was speaking to an educator in the hallway here, you know if you know students, if you have kids who are in junior high or high school and and they love being outdoors and they love, you know, getting into things like this, what are the things that parents might do in order to lead them, you know, towards something that might be of interest like this?

Ben Surpless [00:59:21] Well, I think it's really common that when you're curious about something and you show your curiosity and you engage in a topic, whatever it might be, if it's geothermal energy, for instance, that would be something that your kids are...

Nathan Cone [00:59:36] I mean, it's cool!

Ben Surpless [00:59:38] For instance! But I think that that's I mean, just showing your excitement about anything and and if it's, you know, getting outside. And that's what you're excited about doing, then that's something you should do and bring your kids with you. And I think that when I was growing up, my parents were excited about a whole lot of different things. And so that was part of the when I went to college, I had about 6 or 7 majors that I had in mind. That might be part of it. But but I think that that I think that's healthy. And I also think that's this is just a little commentary. Too many of our students are coming into college saying, this is my major and that's not the way to come into college. I don't think unless you truly are passionate about one thing. But but yeah, I think that that's just in terms of like getting younger people excited. It's if you're excited, then they get excited, too.

Nathan Cone [01:00:30] Good advice. Well, thank you again for being here today. Thanks to Dr. Ben Surpless, Dr. Brady Ziegler and Dr. Saugata Datta, Information and audio from today's program will be on our website. Next week is Thanksgiving week, so I'm going to try and get it up next week, but it'll be out there real soon so that you can share it with a friend. Thank you to Trinity University and UTSA for their partnership. Thanks to Teachers Think Saints Supporters, Culligan Water and San Antonio Water System. We appreciate you. I'm Ethan Cohn. Most of all, thanks to all of you and to Texas Public Radio's members for making this happen. Thanks for your support. We'll see you in February at our next Think Science event. Have a good evening.