We recently published a three-part interview with Chris Reddy. Here, we provide the full text transcript of the conversation, which includes some additional insights not presented in the video interview.
In our three-part interview with Chris Reddy, he discussed the historical and environmental implications of industrial ocean dumping, particularly off the coast of Southern California from the late 1940s to the early 1960s (1–3). He detailed a 2011 research cruise where they used autonomous underwater vehicles to locate and sample containerized waste, revealing high levels of DDT and other chemicals. This research, published in Environmental Science and Technology, led to $16 million in funding for further studies (4). Chris emphasized the challenges of non-targeted analysis and the benefits of using comprehensive two-dimensional gas chromatography. The findings inspired a documentary, "Out of Plain Sight," and he spoke to us about his team’s work and his experience attending the premiere of this documentary.
Yellow radiation hazard waste barrels at the bottom of the ocean , radiation, hazard, waste, barrels, yellow. Generated by AI. | Image Credit: © lapeepon - stock.adobe.com
The below is a full text transcript of our interview with Reddy. To watch the video interviews, you can find them at the following link: https://www.chromatographyonline.com/columns/inside-the-laboratory
Will Wetzel: Can you tell me about the history of industrial scale ocean dumping and its environmental implications?
Chris Reddy: During the last century, at least around the United States, there were multiple locations, both in the Atlantic Ocean, the Gulf of Mexico, and in the Pacific coast, where chemical waste was dumped, either from a barge right over the side, or even a container, not containerized. And often it was legal and allowed. This was a practice that was much more prevalent during the last century up until the 1970s, but I have been studying primarily some dumping that occurred off the coast of Southern California from about the late 1940s and early 1960s.
Wetzel: How do these historical practices kind of influence current policies on waste management and environmental protection on a broader level?
Reddy: In 2011, I was on a research cruise off the coast of California with my colleague, Dave Valentine, who was at UC Santa Barbara, and we had a unique opportunity to use a series of underwater robots or vehicles to look and for some containerized waste that was dumped off the coast of California. But there was no record of any visual evidence or any sample evidence that it existed. We were lucky to find this material, and we were lucky to collect samples. We brought the samples back to my laboratory and analyzed them with comprehensive two-dimensional gas chromatography. We published a research paper that was picked up by the Los Angeles Times, and a reporter wrote a whole series of articles. Those series of articles kickstarted state and federal interest to the point where there's now been $16 million of research funds that have been allocated to expand and understand the extent and the significance of this previously identified containerized waste off the coast of California. So, from a policy perspective to recent discovery, officials are now trying to constrain the significance and what would be the next steps.
Wetzel: Can you talk about the nested approach using autonomous and remotely operated underwater vehicles when you're surveying and looking at these dump sites?
Reddy: One of the reasons why these dump sites have not been identified previously is that they're at 900 meters from the on the bottom of the sea floor. You can't certainly scuba dive to look for this dumped waste. So you have to rely on underwater vehicles to see if you can find them or use other types of devices.
In our case, we use two different types of vehicles, or underwater robots. One of them was called sentry. And sentry is completely autonomous. It has no wire or cable. There's nobody on it. It's just a device that you can lower over the side on a research vessel. We sent it on a mission to map the bottom of the sea floor in the area in which we thought we would find this debris. We brought sentry back on the deck of the research vessel, the Atlantis, and we interrogated that data we collected. And from that data, we could see from the mapping that this vehicle used, we could see a trail of what looked like dumped material. We then used another underwater vehicle called Jason. Jason is a lot bigger, and it’s also unmanned, but it's connected with a big power cord over the side of the boat, and it can last in the water for a long time. Jason has video cameras, two robotic arms, and it has a whole series of tools and equipment that you can use to go right up to where we saw some dumped waste in an open barrel. And we could collect the waste with the robotic arms, so the samples we brought back up to the surface.
From a nested perspective, sentry went and mapped out the area like a hunter-gatherer. In this case, sentry looked and then it sent us on our mission using Jason. One of the exciting parts about being a chemical oceanographer is that we get to collect real world samples. We get to use high tech like these vehicles and other platforms to collect the samples. And then, in my case, I'm often on the boat when we get the sample, so I'm collecting them, and I'm putting them in jars, so I have this kind of physical connection in the Pacific Ocean. And then I go back to my laboratory and work with my close colleague, Bob Nelson, and we analyze the samples with comprehensive two-dimensional gas chromatography, and we're able to see DDT and a whole series of other chemicals related to the production and synthesis of DDT. This is not surprising because a lot of that dump waste was tied back to Montrose Chemical, which was one of the largest DDT producers in the United States in the last century.
Wetzel: Are there any challenges that you encountered when quantifying and characterizing the contamination on the deep-sea floor?
Reddy: In the modern day, when you want to utilize for environmental pollutants, especially in the United States, there are a whole series of methods. The EPA has 8260 and 8270 target volatile organic chemicals and target semi-volatile contaminants, respectfully, and there's a whole series of them. When you do start going into areas that contain dumped waste, you don't have the luxury of knowing what you're looking for, right?
In our case, we were doing a non-targeted search, because we had no idea what we were going to find. We thought maybe we would see some DDT-related chemicals. So that's the challenge is, but it’s also kind of the fun. The fun is developing a new method in flexing our chemical and chromatographic muscles to interrogate these samples and try to understand and tell a story about them. And what was very interesting, and this is where the power of comprehensive two-dimensional gas chromatography comes into place, is that while there was a lot of DDT related synthetic waste, the most abundant chemicals that we were finding in these field samples were related to petroleum hydrocarbons.
Whether or not they were part of the hydrocarbons that might be used as solvents or fuels was unclear, but they may also be containerized waste that was co-mingled from all the nearby oil refineries that are also not too far from where Montrose was. The key point here is that while it is challenging to look for chemicals that you might not have a recipe or a method for, it makes doing science a lot more fun. And it's even a lot more fun when you have the colleagues, like in my case Bob Nelson, and their capacity to use comprehensive two-dimensional gas chromatography to investigate these samples.
Wetzel: The study I looked at reported peak concentration of DDT that was 40 times greater than at the other nearby Superfund sites. Can you talk about this finding and what it says about the extent and the severity of the contamination?
Reddy: Montrose Chemical has been well known to have been related to the contamination on the coastline of Southern California. And historically, when you talk about Montrose chemicals in Southern California, most folks think of the Palos Verdes shelf because the coastline is very close to where the chemical place was. That contamination from Montrose was from outfall pipes that were flushed through the sewerage.
And so historically, when you talked about Montrose, it was thought as a Superfund site, a site that was identified as having significant contamination, and it was legal. The concentrations we saw there were, in some cases, much smaller than what we found in this dump site, which is a lot more offshore, more like 10 miles offshore. We don't know the significance.
Despite the fact that we collected these samples a while back, it's hard to go and collect samples and try to characterize a large area. Oceanographic research costs a lot of money. While there has been $16 million added to kind of assess the significance of this contamination, we really haven't really constrained the significance of it. My colleague, Dave Valentine, is kind of really leading the charge, and he's been going out and collecting sediment cores, which works as a kind of pipe off the side of a boat and that pipe sticks into the mud, and then you can bring it back up. So he's been collecting a lot more cores, kind of like interrogating the areas around the dump site, which has helped make a type of grid. We've been analyzing some of those samples in my laboratory, and some of the work hasn't been published, but what we're finding is that we still see a lot of DDT-related chemicals, but there are also other chemicals that are present. At this point, we have identified areas where they dumped waste, but we have not constrained ourselves to the outer perimeter and determined how much was dumped.
Wetzel: So with these DDT chemicals, what are the ecological consequences of this contamination in these deep sea communities? What's the impact that they have?
Reddy: Scientists always have three responses which frustrate a lot of people, which are “I'm not quite sure,” “I need more money,” and “I need more time.” That’s going to be my same response here, but we can take a step back. You know, DDT was first synthesized in the late 1800s, and Mueller in the 1930s identified the insecticidal properties of DDT. By the 1940s, it was being used widespread and saved a lot of lives to the point where Mueller won the Nobel Prize in medicine and physiology. The problem was that we were using these chemicals with not a significant appreciation about their source, transport, fate, and negative impacts, and that still kind of happens today, which is a little bit frustrating.
Rachel Carson wrote her book Silent Spring, which was published in 1962, and it identified a lot of the concerns about the widespread use of DDT, such as the thinning of birds, shells, and so many other negative impacts. And so that book kickstarted efforts to constrain the usage of DDT. By 1972, DDT was no longer being sold in the United States. It's still being used in some areas today. The problem we have from the 1950s and many other chemicals is that we used it without appreciating the significance of what would happen if it was improperly used or even used overall.
Now we know that DDT has harmful effects at this point, there are some indicators off the coast of California. Sea lions have had a much higher incidence of cancer. Condors are having some thin bird shells. But is there direct evidence that dumped waste is the source of these environmental problems? No, we have no evidence of that, but this dumped waste is a contaminant. It shouldn't be there. And so, it’s often challenging to directly connect the pollutant to an impact, but we want to avoid having that impact by not having that there.
Wetzel: What were the benefits of using comprehensive two-dimensional gas chromatography for the analysis that you were conducting compared to other techniques?
Reddy: The workhorse for looking for organic contaminants is gas chromatography with a variety of different detectors, including mass spectrometers. For the most part, they're one-dimensional. You have a complex mixture of chemicals in your sample, and you inject it into a GC column, and it stretches out all the chemicals based on some physical chemical property. And by stretching them out, you can separate them, which is chromatography, and then you can detect them when you have complex samples where there's a variety of different chemicals with a wide range of physical and chemical properties. Some of them overlap the capacity of one single gas chromatographic column to separate them, so it is not good enough, and that's when you turn to advanced techniques.
When you have complex samples, you will be stymied by having only one-dimension of separation, even if you have a great high-resolution mass spectrometer, which adds a lot of significant power. When you add a second-dimension column, it has a different property. In our case, we were separating essentially by boiling point in the first dimension and then relative polarity. We’re taking the field sample, and we're pulling it and stretching it to create a map, and that map allows us to tease apart chemicals that otherwise would be colluding in the first dimension. That becomes incredibly significant when you're doing non-targeted analysis because you don't know what you're looking for.
One of the best ways to identify is getting a mass spectrum. It even gets more effective when you have a high-resolution mass spectrum because then you can start to get what we call an accurate mass, which allows you to identify the elements that are present. But the other thing is that where these chemicals sit on this two-dimensional plane also tells you a little bit about their properties. That is how fast they might evaporate into the atmosphere, how fast they might dissolve into water, even potentially whether they're toxic. And so, two-dimensional gas chromatography is more than making pretty pictures. It allows you to separate, identify, interrogate, and get a sense of the environmental impact. We've been using comprehensive two-dimensional gas chromatography for 20 years, and it always amazes us about what it can do for our science.
Wetzel: So one thing that stood out to me in our initial email correspondence was that your research that you and your team did was inspiration for a recent documentary that you attended the premiere of. What was it like attending that premiere, and what was highlighted in the movie that directly related back to the work that you and your team did?
Reddy: I mentioned a little bit earlier that when our first research paper came out in Environmental Science and Technology, my colleague and the lead scientist, Dave Valentine at UC Santa Barbara, was interviewed by a reporter named Rosanna Xia, who's at the LA Times, and she wrote a whole series of follow-up stories to the point where there was interest in doing a documentary.
Therefore, Rosanna aligned with some other folks, and they produced this documentary called “Out of Plain Sight,” and it really kickstarts the discovery of this dumped waste and the fact that we could characterize it and identify DDT and these other chemicals. The documentary tells the story about finding them, what's the ongoing research, and what might be the potential impacts. It's a great science story, and Rosanna went to a variety of different scientists to identify and talk about the problem. You have TV shows like CSI where there's one guy or one person who analyzes the sample, slaps the hand down, and says, “You know that guy is guilty, right?”
That doesn't happen in environmental cases. Very rarely does one scientist or one team save the day. You need an ensemble cast of chemists and other types of chemists, geologists, physicists, and biologists to be able to put together a story because it's more than just identifying the problem. It's great that you can identify the problem, but to me, what's most rewarding is to try to constrain it and understand what we can do next to make this bad thing from getting worse.
I went to the premiere. It was in New York City. I have three kids. My wife and I didn't think we could bring all five of us together, so I brought my oldest son, William, and it was real kick. You know, he sat in the front row with the VIP, next to my colleague, Dave Valentine, who happens to also be one of my closest friends, and he's the star, right? So, you're a scientist, you're getting to see your colleague you've been working with for 20 years. We were on the boat together in the control room, watching the video of the robot seeing it for the first time. And you know, going from seeing the video of the discovery to seeing the video of us discovering it years later, it was pretty rewarding.
Wetzel: Did you appear on screen?
Reddy: In this case, in my 15 seconds of fame, I talked about how you collect these samples. How do you grab a sample that's 1000 feet at the bottom of the sea floor and be able to bring it back up? You know, you can't just lower a shovel down and try to bring that shovel back up to the surface and keep its integrity. And so, I talked about that, but to be honest with you, I wouldn't care if I was in the movie.
But what's important as well is that these are the types of science stories that the public, future scientists, and officials need to hear that see how science works. I think a lot of the problems we have in society is not necessarily that folks might not be able to interpret a gas chromatogram, but rather understanding how science works, how it's incremental, how it's ever expanding, how it's self-correcting, and why scientists do what we do. And so, when you get to see stories up on the video that talk about the science and talk about the science that I'm involved with and your 10-year-old son is sitting next to you, that's pretty cool.
Wetzel: Any last thoughts before we wrap up?
Reddy: I want to just underscore that I've published probably 80 or 90 different research papers using comprehensive two-dimensional gas chromatography from working on the Deepwater Horizon oil spill, which I spent about eight years of my life on. My success as a principal investigator is directly tied to my colleague and laboratory manager, Bob Nelson. The graduate students and postdocs and colleagues I had also underscores that not one scientist of any discipline might save the day; it takes a team. I might run my research group, but the stars of the show are the folks who are in the laboratory and putting the GC vials into the autosampler and making them run and interpreting them. And in my case, I've had this guy, Bob Nelson, and we're lucky to work with a lot of the manufacturers such as LECO, who has been generous and an incredible supporter of us, and we've been using their platforms for a long time.
This transcript was edited for clarity.
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