Episode 3: The Hidden Pipeline: How Human Pollution Seeps into the Sea

Episode Description: Fish full of pharmaceuticals. Submarine groundwater discharge is quietly delivering human contaminants—like heavy metals, fertilizers, and even antidepressants—into our oceans. In this episode of Oceanography, marine geochemist Dr. Tristan McKenzie explains how these hidden pathways are impacting coastal ecosystems around the world. Drawing from fieldwork in Hawaii and Sweden, he breaks down the science behind groundwater pollution, shares the results of a global contamination risk map, and discusses the surprising ways contaminants disrupt both marine life and biogeochemical cycles. You’ll also learn why some of the world’s most biodiverse coasts are at highest risk—and how you can help. This is a deep dive into ocean contamination, climate interactions, and the data behind it all. 

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Episode Guest: Dr. Tristan McKenzie

Learn more about Dr. Tristan McKenzie on his website here and the University of Gothenberg

Follow  Dr. Tristan McKenzie on Blue Sky

Find more of  Dr. Tristan McKenzie’s work on Google Scholar

How Gutting the EPA's Research Team Could Impact Clean Air and Water Rules by the Scientific American

EPA likely to move to further limit federal protections for wetlands by AP News

Fish off the coast of Florida test positive for pharmaceutical drugs, says study by CNN

Episode Transcript  and more information on the Pine Forest Media website

Follow Pine Forest Media on Instagram @pineforestmedia

Hosted, produced, and edited by Clark Marchese 

Cover art by Jomiro Eming

Theme music by Nela Ruiz

Listen to South Pole on Spotify or Apple Podcasts

Listen to Plastic Podcast on Spotify or Apple Podcasts

Listen to Something in the Water on Spotify or Apple Podcasts

Transcript:

Clark Marchese (00:12.174)

Hello there. Thank you so much for joining us here on Oceanography, the podcast that dives deep into the science of our oceans, the latest in marine research, and the scientists working hard to better understand and protect our blue planet. And today we have a code 2319.

Clark Marchese (00:58.51)

Alright, today we have a code 2319. For anyone who has not seen Monsters Incorporated, that alarm code is meant to signify that an artifact from a child's bedroom has contaminated the monster world. Which means today on the podcast we are talking about ocean contamination. Now, this is not an alarmist episode. However, more and more research studies are coming out that are finding larger quantities of contaminants in the ocean that scientists, like the one we'll be speaking today, would like to call attention to. Specifically, heavy metals, fertilizers, and even pharmaceuticals, just to name a few. I'm going to link a news article in the episode description that talks about a study that came out in 2022, and it definitely went through its rounds of internet fame. It was all over my algorithm for a while. But a team of researchers in Florida found that a bunch of fish in the Florida Keys were testing positive for antidepressants. This is a longitudinal study, and they collected data from 2018 onwards, so several years. One fish that they looked at had as many as 17 different pharmaceuticals. And that was just one study that happened to sort of break through into the media streams. But there is an emerging body of work looking at the concern of ocean contaminants and the pathways through which they enter. Today, we are going to be talking about several. joining us is a researcher named Dr. Tristan McKenzie, who is interested in how submarine groundwater discharge acts as a pathway for human source contaminants that disrupt marine environments in ways we're only beginning to understand. Dr. McKenzie is a researcher

and the Department of Marine Sciences at the University of Gothenburg in Sweden. His work combines geochemistry, hydrology, and machine learning to track human impacts on coastal groundwater systems. He has studied everything from nutrient pollution to pharmaceuticals in the ocean, and today will be diving into his recent publication, Metals in Coastal Groundwater Systems Under Anthropogenic Pressure. We'll talk about where some of these contaminants come from, how they're impacting the ecosystem, and why some of the most vulnerable coastal areas on the planet are also the most at risk for contamination. and toward the end we'll talk about what intervention methods may be effective in reducing our impact. Dr. McKenzie will also share some insights from his fieldwork, digging holes in the beach, kayaking along coastlines, and using radioactive tracers to track groundwater flow. But before we get started, if you are enjoying oceanography and you want to support science communication like this, I would ask you to consider joining our Patreon. For as little as $3 a month you can help us keep this show going and others like it in the Pine Forest Media Network of environmental podcasts.

Clark Marchese (03:23.798)

Also, a portion of the proceeds we collect on Patreon will be donated to other science communication and research projects that our contributors will get to help us choose. While you're in that episode description, you might consider giving us a one tap five star rating. And if you want to write a review, we'd love to hear what you think about oceanography so far. All of these things help us reach more people in a time where science communication is more important than ever. All right, I think with that, we can go ahead and get started.

Clark Marchese (04:03.054)

Okay, let me see. I've got my questions here. Okay, we are recording. Hello, Dr. Tristan McKenzie. Thank you so much for taking the time to come on Oceanography today. First things first, why don't you tell us a little bit about yourself and introduce your research?

Dr. Tristan McKenzie

Yeah, for sure. And first I want to say thank you, Clark, for the invitation to talk with you today. I'm a researcher in the Department of Marine Sciences at the University of Gothenburg in Sweden. I completed my PhD in geology and geophysics from the University of Hawaii at Manoa. That was in Honolulu. And broadly as a researcher, I'm interested in understanding anthropogenic impacts on the coastal ocean and groundwater chemistry. I use geochemical tracers to follow groundwater pathways and flow. And then I pair these with other tracers, such as pharmaceuticals and metals, to understand the human source aspect. And most of my research focuses more specifically on a submarine groundwater discharge. And this is groundwater that slowly seeps out to the coastal ocean.

Clark Marchese 

Okay, incredible. We have some vocab words it seems that we'll have to unpack, but first I'm so happy to have you here today. And this is one of the reasons I like the topic of ocean science as a podcast, because I get to talk to researchers that are coming from all different backgrounds and looking into all different kinds of things. Last week was a marine biologist, now we have a geophysicist. So cool. Okay, let's define some terms, shall we? We will work our way up to geochemical tracers, but let's start with a warmup. How about you tell us what groundwater is?

Dr. Tristan McKenzie

Yeah, absolutely. groundwater, in general, you can think of it as an underground river that's flowing very, very slowly, like on the time scales of hundreds to thousands of years. And instead of flowing freely, like rivers do on the surface, groundwater flows through tiny spaces in rocks and particles. So many people might think about groundwater more in the context of inland sources, such as well or drinking water, but groundwater is everywhere. And so to exemplify what submarine groundwater is, have you ever dug a hole at the beach and then you reach like this

Dr. Tristan McKenzie (05:54.296)

kind of pool of water. That's groundwater. That is groundwater. That is the coastal aquifer you are tapping into. This water, once you get to the coast where you might go into the surf or whatever,

Clark Marchese 

I sure have.

Dr. Tristan McKenzie (06:08.13)

then this rat water will come out there as submarine groundwater discharge. And so that's kind of what we're focused on here. You can kind of think also of water as a conveyor belt. So when we're thinking about in the context of pollution in that it transports things from one place to another. So water is just kind of the vehicle. And so in the context of pollution, then river-based pollution is often easier to detect because we can see it. But groundwater, perhaps for obvious reasons, it's more challenging to both observe and recognize when something is off. And that's important because groundwater often carries higher concentrations of a variety of contaminants. And that's because whatever we do on the land, be it mining or spraying pesticides, that then can seep into the ground, which will eventually seep into the groundwater and then eventually come out at the coast, if you're close to the coast, as summary groundwater discharge.

Clark Marchese

Okay, so a couple of things here. If anyone has listened to any of our other Pine Forest Media podcasts, they may have heard quite a few discussions about plastics. We spend a lot of time talking about just how abundant and invisible human pollutants can be and how microplastics, as just one example, can infiltrate and spread through things like soil and water systems or even the literal air. But in this case, you're focusing on a range of different contaminants that can do the same thing. So maybe you can tell us which ones you're looking at and also how they infiltrate these groundwater systems in the first place.

Dr. Tristan McKenzie

Yeah, absolutely. So a lot of my research focuses on several types of contaminants, nutrients, which I think I'm going to talk less about today, but also metals and pharmaceuticals. And if we take at the example of metals, metals can reach the groundwater systems from a variety of sources. Basically we can look at mining, industrial practices, wastewater, agriculture. These are all examples of sources of metals that then end pesticides, pharmaceuticals, et cetera.

Dr. Tristan McKenzie (07:56.962)

that then can reach the groundwater and be transported via submarine groundwater discharge. And I want to clarify that, for example, in the example of metals, they're not inherently bad in themselves. Many metals are actually vital for ecological functioning, but… that's typically in significantly lower concentrations than what we observe in contaminated sites. And in particular, humans have definitely shifted the locations where we find specific types of metals, as well as driven significant increases in metal concentrations in the environment. And that's the excess that is really the problem here.

Clark Marchese

Got it. So I have a question. If metals are found naturally in the environments you're looking at, at what point would we consider a given area to be contaminated?

Dr. Tristan McKenzie

Yeah, so in a lot of cases, in a lot of metals, there's actually a government set threshold that we would look at. Yeah, it really depends on the type of metal. And there are a lot of metals, so not all metals are equal. We might have more toxic ones, such as mercury or lead, and then others that maybe are a little less harmful or are only harmful in significantly higher concentrations. And if you want to look at, just an example of one that we might find commonly in a small concentration, like zinc. Zinc is often found in very small concentrations in rocks, but frequently we find it in relatively higher concentrations because of mining, wastewater, or for instance, anti-fouling boat paints is a common source of zinc in the coastal shill.

Clark Marchese (09:21.75)

Okay, well, I guess I want to know also where you've done research. Are there any regions or areas that you've looked at specifically? I'd also be interested to learn what you discovered there.

Dr. Tristan McKenzie

Yeah, for sure. In the metal context, mostly I've done work in Hawaii. This was during my PhD. And I was working in a very contaminated area. So my interest in this area was actually because there was evidence that there was wastewater coming out from cesspools to the coastal ocean and via submarine groundwater discharge. so that work was really focused more on pharmaceuticals, but I also took samples from metals and we kind of confined all of the metals associated with higher wastewater inputs there.

Clark Marchese 

When you were speaking earlier about the sources of metals, you mentioned mining, which I found somewhat intuitive. But if I am asking myself, which I am now, which metals might come from, say, agriculture or wastewater, I'm drawing a little bit of a blank. So which metals are associated with, say, wastewater systems or cesspools?

Dr. Tristan McKenzie

Yeah, that is a great question. And it also depends, like, what is the type of wastewater you're looking at? because wastewater, OK, you have the example of, let's say, sewage from humans, but you also have wastewater from hospitals. have wastewater from industry, technically would come under wastewater. So there's also a lot of different ways to tease apart wastewater. the types of metals that we might find, say, in like sewage. It's typically a combination of disinfecting products, the products that we would use in soaps, byproducts of various pharmaceutical, like there are a lot of things that we ingest that have like a little extra metal in them. It's, I mean, there's like a list of 15 metals that would be common. So that's why I'm like, how do I pull out a specific one? And then also say like lead, lead is often in pipes, right? And then that'll of course come out in the wastewater.

Clark Marchese (11:14.606)

Okay, so that is a long list and those are just some of the metals of concern. So I imagine the answer to this question will have a lot of variance, but what are some of the consequences that these contaminants are having on the marine environment?

Dr. Tristan McKenzie

Yeah, so it depends on the contaminant itself. I guess if we look at kind of where I'm focused, and that's the coastal aquifer, these coastal groundwater systems, and if you consider that this area is a filter, or often acts as a filter, at present, we can kind of think of this as a way of capturing the metals that are coming in. There's kind of several ways to look at it. So there's the metals that are toxic, inherently, they don't serve as a micronutrient, for instance. So like zinc. is a micronutrient, we need some in our body, can process small amounts. But for instance, metals such as like mercury, lead, or arsenic, these are all examples of toxic metals. And the scarier thing about them is that they also bioaccumulate, and that means that our bodies cannot get rid of them faster than it is metabolized, or we don't even have a pathway, and that means that it accumulates over time. So there's kind of this category of, let's say, metals that negatively impact the health of humans and marine wildlife, and that would be one category. And then there are other categories, such as metals that interrupt or interact with natural biogeochemical processes. So they might interact with like the microbes that process maybe other things, other processes. for instance, neutrification, this is where, it's a big problem. I'm in a lot of areas globally, and this is caused by excess nutrient inputs, often from agriculture to the coast.

Clark Marchese

Quick aside, I did a little digging for some examples of eutrophication, and I learned that essentially when this process happens, it creates what is called a hypoxic or anoxic condition, meaning low or no oxygen. And this sort of suffocates the marine life in the surrounding area. A striking example is the Gulf of Mexico's dead zone, one of the world's largest hypoxic areas, largely driven by fertilizer runoff from Midwestern farms via the Mississippi River.

Clark Marchese (13:16.76)

This excess nitrogen from fertilizers stimulates massive algal growth, leading to oxygen depleted waters that can no longer support fish or shellfish or other marine organisms that can devastate the ecosystem as well as local fisheries that depend on them.

Dr. Tristan McKenzie

Right, so that would be an example then of how a metal could come in and disrupt, you know, kind of what were the natural processes that we anticipate. So metals, metals in the environment are, as I was saying, reactive to a lot of different environmental processes. And one of these processes that they interact with is pH. So metals, many metals tend to be more soluble and reactive under more acidic or lower pH values. There are other kind of environmental parameters that are like this too. So it's like, for instance, salinity. Increasing salinity actually drives the release of many metals from aquifer material to the coastal ocean. so in the context of ocean acidification specifically, there's some evidence that certain metals can interact with the photosynthesis respiration process and that then leads to an impact on ocean acidification. If we break this down a bit further, and ocean acidification is the process where CO2 levels are increasing due to human source emissions, primarily from fossil fuels, and then that leads to the formation of excess carbonic acid, which then leads to an overall decreasing pH in the ocean. Okay, so we have that.

Clark Marchese 

Side note, listeners, maybe ocean acidification is a huge topic that will likely have its own episode at some point.

Dr. Tristan McKenzie (14:51.054)

But then some metals, for instance, mercury and lead, these can then interact with marine photosynthesis. And then that then can amplify or result in more acidification in marine systems.

Clark Marchese

Okay, so these are some potentially really big consequences. Just to recap though, I heard two main categories. The first is when metals are straight up poison, which we should also note that it's not just poison for the fish. That poison makes its way back up to us through the food chain. But the second category, which is metals actually change the chemistry of the ocean, which I imagine will have varying levels of impact depending on the metal, the ecosystem, the scale, et cetera.

Dr. Tristan McKenzie

I think it's highly dependent on the local inputs. because locally, if you have a coastal mine, which these are remarkably not uncommon, there's going to be, you know, any of the mining runoff will have pretty much no filtration before it reaches the coastal ocean. So that's kind of a direct input. And so then what kind of ecosystem you have there, well, does that really matter? I don't think, you know. And there's kind of two perspectives. There's the local human pressure that's going to put, you know, so what are the local inputs, mining, industry, wastewater, how are we treating them? And by that, mean, how are we removing metals before discharge in these areas? And then there's the environmental factors. So if you have a region that's highly sensitive to, for instance, sea level rise, well, that's going to be more sensitive than an area that's perhaps not.

Clark Marchese

Okay, this is getting directly to my next question. I came across something in an article you wrote titled, Metals in Coastal Groundwater Systems Under Anthropogenic Pressure, which was sort of a synthesis of behavior drivers and emerging threats. In this article though, there are a series of maps like of the whole entire world. And these maps that you made are meant to show and identify the areas of the greatest risk. And you called it a global hotspot risk assessment.

Clark Marchese (16:44.024)

So since the listeners of the show won't have a visual map in front of them, can you sort of tell us what went into creating these maps and what they reflect?

Dr. Tristan McKenzie

Yeah, absolutely. All right, so we're thinking about these two different types or categories of influence, right? We have this local human pressure, which I've said can come from a presence of mining or industry or the degree to which wastewater is treated. Untreated wastewater obviously has a lot more metals than treated wastewater. And as well as the local population density, the more people we have, the more pressure, human source pressure we have on a local coastal area. The second type of influence then goes into these environmental factors, and that includes both baseline conditions, for instance, the rate of submarine groundwater discharge or the presence of certain types of soils that may be naturally more acidic, but as well as climate change hazards such as sea level rise, storms, increasing temperature, et cetera. So for this global risk hotspot model, we combine these factors to identify the regions that may face the highest risk from metal pollution or metal release and pollution.

Yes, this map has lots of colours and it's very satisfying. But maybe to bring up some salient points from it, we found that the highest risk category, this is areas with very high population density. So think like the most, you know, the biggest cities in the world where people are just quite crammed in a small amount of area, were also areas where there was a high percentage of untreated wastewater, active mining in the coast, and as well as high rates of submarine groundwater discharge. And these areas where these areas all overlap, that's about 4 % of the global coastline. So these are our highest risk areas. But if we then combine the three highest risk categories, which share a lot of the same characteristics, but maybe aren't quite as high in population density, or maybe the percentage of untreated wastewater goes down to maybe 50%, which is still quite high, then we're looking at about 36 % of the global coastline. it's particularly concentrated in the tropics, which is also one of the areas that is most

Dr. Tristan McKenzie (18:40.832)

sensitive to climate change impacts.

Clark Marchese

Okay, my brain is asking me then if we have this map that shows us the most vulnerable areas, can this data inform any sort of intervention strategy?

Dr. Tristan McKenzie

Yeah, that was my, I guess, my secret hope. Not so secret hope. But with this research, it's okay. So if we can identify areas that should be prioritized, for instance, then we can maybe do something about it or try to kind of hit the nail before it's too late.

Clark Marchese

Okay, I've made a note at the end to ask you if there's anything that we can do about these contaminants or intervention strategies, but before we get to solutions, let's finish with the problem. Metals, as you've mentioned, are not the only contaminant that you have investigated. I understand you're also currently conducting research about pathways of pharmaceutical contamination off the Swedish coast. Can you tell us a little bit about this project and how pharmaceuticals differ from metals in their impact on the marine environment?

Dr. Tristan McKenzie

So in this project, we're trying to understand the role that submarine groundwater discharge plays in delivering emerging contaminants. And that includes not only pharmaceuticals, but also pesticides and industrial chemicals. And a lot of these compounds actually have the same human sources as metals, but there's an additional layer that these compounds have an exclusively human origin, right? Like we made them. There's not a natural source of ibuprofen, for instance, in the world. What's interesting about pharmaceuticals and where they can actually overlap

Dr. Tristan McKenzie (20:10.346)

a with metals from a, from a chemical perspective is that pharmaceuticals are one designed to be highly bioavailable and water soluble, right? So that means that if we take an ibuprofen, for instance, that our bodies can absorb it and it can treat the pain or whatever you're, taking it for. But that's, that's also a problem because when we make these medicines. They are designed to be a one-size-fits-all for kind of every person on the planet, which means that often a large percentage of the active ingredient actually comes out in our excrement, which then it can become an environmental problem. Like metals, then pharmaceuticals are complex in their chemistry and how they interact in the environment, but we see a lot of the same climate change controls. for instance, increasing salinity, lowering pH as potential mechanisms for releasing from aquifer materials. But I should also say that pharmaceuticals are quite, the compounds are quite a bit more complicated and we don't know nearly as much about them. It's kind of a newer area of research that we're able to even detect these compounds in the environment.

Clark Marchese

Are there any particular pharmaceuticals of concern?

Dr. Tristan McKenzie

Yeah. So in this study, we're mostly targeting a broad range of pharmaceuticals, and that's because we need to know what kinds of compounds are present first. But if we look from a more general perspective, we do have awareness that certain types of pharmaceuticals impact the environment more negatively. So for instance, antibiotics in the environment have been linked to the growth of antibiotic-resistant bacteria. Perfect.

Dr. Tristan McKenzie (21:37.686)

Right? Very fun. And then also for another example, estrogenic compounds, they've been shown to disrupt reproductive systems in some species of invertebrate or fish and in absolutely minuscule concentrations. We're looking at like one nanogram per meter and that's kind of, that's equivalent to 0.001 parts per billion. So these are quite, quite small concentrations can actually have a pretty major impact.

Clark Marchese

Are these ones having a similar impact as the metals that are completely altering the ocean chemistry?

Dr. Tristan McKenzie

Yes, but we don't really under... this is more poorly understood.

Clark Marchese

Okay, and I also have to know, what does a day in your life look like if this is your job? Because if I was to design a study that was trying to quantify pharmaceutical concentrations in submarine groundwater discharge, I wouldn't have the foggiest idea of where to begin or how to do that. So can you tell us what field work looks like in this type of study?

Dr. Tristan McKenzie

Yeah, yeah, and the field work is quite fun. I have to get really nerdy for a second. I use groundwater tracers and a naturally occurring radioactive tracers radon and radium. These are naturally in the aquifer material and means they're great tracers for groundwater. So this is how I'm tracing the groundwater. And you can then build a fancy, you can do fancy calculation that basically will tell you how much is coming out and then measuring these various pharmaceuticals. So mostly what this looks like is me digging holes at the beach.

Dr. Tristan McKenzie (22:57.294)

pumping up water, people walking by being kind of confused, like why are you digging a hole and what are you doing with all this fancy science stuff? And then kayaking out along the coast and then just measuring these, you know, collecting bottles of water. It's actually quite

Clark Marchese

Hey, I didn't know what you're going to tell me, but I did know that it was going to be amazing. Okay, we did make it around the corner to mitigation. And I guess to enter this topic, I'm going to bring it back to plastic again, which is a separate contaminant than the ones that we talked about. But with plastic, there is a lot of it that we use for things that we rely on, right? There's also an enormous amount of unnecessary and excessive plastic production out there. So it's not hard to imagine how we can reduce our impact. However, today you've told us that some of these sources of contamination are wastewater infrastructures and hospitals, which seem to be sort of quite vital in our societal functioning, but we have this very handy risk assessment map that you've made. So I'm wondering what intervention methods might look like and if you are aware of any successful mitigation strategies out there.

Dr. Tristan McKenzie

Yeah, yeah, absolutely. I think more broadly there, I think there's some pretty powerful examples of how scientific and medical research have led to changes in government regulation. So for instance, the removal of lead and gasoline or lead paint and toys, right? And so these are, I think, examples that people are more familiar with. But I can think of a more, or a pretty impactful example in the context of submarine groundwater discharge. I was not involved with this, but it was driven by several of my colleagues at the University of Hawaii. And basically there was a wastewater treatment plant on Maui disposing waste into underground injection wells. And then the researchers were able to directly trace this waste coming out through the submarine groundwater discharge to the coast. And then this was then identified as a possible violation of the Clean Water Act. And the Clean Water Act prohibits the discharge of any pollutant to navigable waters from any point source by any person. But in this case, there was not a clear, it was not so clear because groundwater wasn't considered a point, I mean, it's typically not considered a point source. But in this case, well, it looks like it could be. And so this actually went all the way up to the US Supreme Court, which ruled that groundwater in some court cases can be considered a point source. And in this case specifically, that the wastewater treatment plant was in violation of the Clean Water Act. Wow. So I thought this was pretty cool. That was a win for groundwater and submarine groundwater discharge research.

Clark Marchese 

Okay, thank you for sharing that. I'm going to look into it because where science informs policy is sort of like the sweet spot of my converging interests, that's great to hear. And it's also really uplifting because that doesn't just apply now to that one well in Maui, right? A Supreme Court decision is a pretty wide-reaching sphere of influence.

Dr. Tristan McKenzie

Exactly. It starts with the precedent.

Clark Marchese

Side note to listeners, if you love clean water and you want to have it and you think it's nice, you may be interested in what you'll find in the episode description, which is a number of news articles that explain what the current US administration is doing to weaken the Clean Water Act and the Environmental Protection Agency, which is the primary body responsible for enforcing it. Okay, now I want to ask you, and before I do, I'll say I'm always wary to kind of shift the responsibility onto the public or the individual when it's clear that, based off of what we've discussed today that addressing these problems will require sort of sweeping, overhaul, systematic change. However, some people, like myself, can feel empowered by taking small actions. So on an individual level, is there anything that we can do, you know, ourselves in the immediate term to reduce the contamination levels of metals and pollution in the ocean?

Dr. Tristan McKenzie (26:37.708)

Yeah, yeah. mean, right. So I also share your hesitancy to put the, I guess the, yeah, for the person to take the responsibility, but there are, can do. And I think one of the biggest things is being cognizant of your consumption and your waste, the types of products you use and how you dispose of them. So for instance, proper disposal of electronics. You have an old computer, you don't just throw it away. You bring it to an electronics disposal facility because then you are limiting how much that can interact with the environment. should be then disposed of in a proper way. Batteries, proper battery disposal. people are pretty good about this, but I will say in the US, I did not see much. You know, most people just throw a dead battery in the trash. You shouldn't do that. That has environmental impacts. And then I think being cognizant of just the products you use, paints. Do you, if you have a boat for some reason, are you using biofouling on it? What are the types of products you're using? Do you put pesticides on your plants? And how is that connected to the water system. So there's a lot of small changes that we can all make in our everyday lives to reduce pollution. And then also, I think what might have a broader impact is just supporting water quality regulations. A lot of times these are small or larger, say like if you're voting in the US, state-based initiatives or county-based initiatives. But these actually do shift the culture, society, and also waterways and often in many cases.

Clark Marchese

Okay, I really like those answers. I think it could be really easy to feel overwhelmed or discouraged, you know, by the voices in our heads telling us that what we do doesn't matter, but those are actually really great concrete and effective ways to make a difference. So thank you for sharing. Well, as we're coming to the end of the episode, I know that we could keep going down different wormholes for probably hours, but I want to ask you if there's anything that we didn't talk about today that we would be absolutely kicking ourselves if we forgot to mention about any of these topics?

Dr. Tristan McKenzie (28:31.736)

You know, I think we've actually did a a good tour. I mean, I can talk about all of this quite, quite a lot. So if it's good to stop me, but I do want to thank you for the invite and of course the interest on the topic.

Clark Marcese

No thank you. And in that case, guess my last question for you is where can people find you and follow your work and learn more about this?

Dr. Tristan McKenzie

Yeah, absolutely. guess first off, I have a website, that is drtristanmckenzie.com or alternatively, I'm on Blue Sky as h20psi.

Clark Marchese

Okay, I'm gonna go follow right now. That's such a cool handle. And I guess this is the part where I say thank you so much for giving us your time today. Thank you for teaching us about these contaminants and also for your really important research in this space.

Dr. Tristan McKenzie

Absolutely. Thank you, Clark.

Clark Marchese (29:18.764)

Alright, another major thank you to Dr. Tristan McGenzie for joining us today. And I just want to advertise to our listeners one more time that the link to our Patreon account is in the episode description. So if you found this episode was interesting, or if you thought that the things that we talked about were important, and you're interested in supporting us and continuing to share scientific research like this, to keep making our shows and to support other science communication projects, that is the best way that you can help us out. And we really thank everyone who is supporting us in that way, especially now in a time when scientific research and our environment are facing some major obstacles. But we will keep doing what we can to get the word out to as many people as possible. And we thank you for your support along the way.

Clark Marchese (30:01.42)

You have been listening to Oceanography, a Pine Forest Media production. You can find more information about the podcast and this week's guest in the episode description. Cover art for the show was done by Joe Miro-Emming and the music you're listening to was done by Nila Ruiz. The show was hosted and edited by me, Clark Mrakezi, and you can find more information about Pine Forest Media and our other science podcasts at pineforestplus.com or follow us on social media at Pine Forest Media. All right, that is all I have for you today and thank you so much for listening.