The Santa Barbara Scientist Who Found Poison in the Pacific

David Valentine Discusses Discovering DDT Dumping Ground in Waters off Catalina Island and Charting New Course at UCSB

The Santa Barbara Scientist
Who Found Poison
in the Pacific

David Valentine Discusses Discovering
DDT Dumping Ground in Waters off Catalina Island
and Charting New Course at UCSB

by Callie Fausey | August 31, 2023

A DISTURBING DISCOVERY:  In 2011, UCSB scientist David Valentine discovered a massive DDT dumping ground in the waters off Catalina Island. Today, as he prepares to launch a new marine science major at the university this fall, he says he’s still “trying to understand what happened and where it’s all going.” | Credit: Ingrid Bostrom

Pure DDT — the toxic insecticide banned in the U.S. in 1972 (but still in use in other parts of the world) — is poisoning the marine environment off the Los Angeles coastline near Catalina Island. The harmful chemical has blanketed the seafloor since hundreds of tons of DDT were dumped into the water more than 50 years ago.

UC Santa Barbara scientist David Valentine is the one who discovered the startlingly high concentrations of DDT 3,000 feet below the water’s surface, surrounding an underwater graveyard of leaking barrels filled with unknown chemical substances.

He says that it’s “goo-ifying the junk” of male sea lions (as well as destroying their spines, riddling them with tumors, and killing their kidneys) because of the nightmarish combination of herpes and toxic chemicals such as DDT (dichloro-diphenyl-trichloroethane) and PCBs (polychlorinated biphenyls). 

In fact, the type of urogenital cancer only caused by that horrific duo is responsible for nearly 25 percent of adult sea lion deaths. 

“It is the gnarliest cancer,” Valentine told me as we sat on the deck of a coffee shop in Goleta.

The sun was beating down, and Valentine was dressed casually, as someone might expect for a Santa Barbara–based oceanographer — baseball cap, cargo shorts, polo, backpack. But even with his laid-back appearance, it was never lost on me that he takes his work seriously. 

“Just think if 25 percent of all human deaths were from one cancer,” he continued. “It’s an insane number — DDT is definitely part of that story.”

That’s just one of the problems associated with the stubborn, unforgiving compound polluting our ocean. Recent discoveries by Valentine and his fellow researchers show that it hasn’t broken down, remaining in its most potent form in high concentrations across miles of seafloor.

Efforts by Valentine and other researchers are now underway to map out the seafloor between the Los Angeles Coast and Catalina Island to determine how bad the problem really is. So far, the results have researchers feeling less than optimistic.

They’ve found that DDT was potentially dumped in two areas off the coast — Dumpsite 1, just northwest of Catalina Island in the Santa Monica Basin region, and Dumpsite 2, east of Catalina and 10 miles offshore of L.A. in the San Pedro Basin. Not only that, Dumpsite 2 seems to have no clear outer boundaries to the vast swath of ocean floor covered in debris and contaminated with toxic chemicals.

This chemical curse was bestowed upon the sea primarily by the nation’s largest DDT manufacturer, Montrose Chemical Corp., which operated a plant near Torrance from 1947 to 1982 and produced an estimated 800,000 tons of DDT over those 35 years. They poured the stuff straight into the water not far from the Channel Islands, which is a nursery for sea lions in California.

“They were manufacturing tons upon tons of this stuff,” Valentine said. “And they had pretty atrocious waste management practices.”

A Persistent Poison

Who knew that a colorless, odorless, tasteless compound once considered a Nobel Prize–worthy prevention method against disease-causing insects would hang around like a bad smell for decades? 

Certainly not the 1950s housewives who sprayed it around their houses (including in nurseries), bought DDT-infused wallpaper, and were sold a retro, pastel promise that it was necessary for a happy and healthy home free from pests. Definitely not the kids who would play in the clouds of DDT sprayed down their streets to kill nearby mosquitos. Nor the military, which viewed it as the ultimate protection for soldiers against typhus and malaria.

Detail of a 1947 Pennsalt chemicals advertisement in Time magazine. | Credit: Courtesy

Valentine said it’s still causing issues in humans, including breast cancer, diabetes, birth defects, and obesity, and it has been recently shown to be passed down through generations. It was found that if a pregnant woman was exposed to DDT in the ’50s and ’60s, they could have passed it on to their granddaughter in the womb since the eggs of females develop very early in the embryogenesis process. 

“They’re also starting to see that human breast milk often has some amount of DDT in it, even though it’s been banned for agricultural use since 1972,” Valentine said. “It’s still around, still getting into people.”

No regional linkages to effects on human health have been discovered yet, or at least publicized. But Valentine says he thinks people will start looking now to see if there’s more of a magnified effect in Southern California due to the new implications of how much DDT has proliferated off the region’s coast.

A Harrowing Discovery 

Valentine began his research journey by immersing himself in the study of gas, particularly methane gas seeping from the seafloor. 

However, his fascination quickly shifted to the oil that seeps out alongside it, which happens right offshore of Santa Barbara County in the oil seeps. During his tenure at UCSB, he’s also been involved in efforts to identify and seal leaky oil wells near Summerland Beach.

“Environments, microorganisms, chemicals — I’ve always enjoyed those mixtures of things,” he explained.

In 2010, Valentine was happily plugging away as a professor at UCSB when the catastrophic BP Deepwater Horizon oil spill occurred in the Gulf of Mexico — widely recognized as the largest marine oil spill in history. The incident was a turning point for the resident oceanographer.

“I mean, the rig went down, and then environmental catastrophe unfolded afterward,” he recounted. “I started studying that immediately.” 

He went out while the oil was still flowing and secured federal assistance to assess the spill’s impacts on the deep ocean and seafloor. “There are not very many people in the world that think about those questions academically,” Valentine explained. 

Employing his UCSB lab group, Valentine worked on figuring out where all that oil was going and what was happening to it, eventually unveiling maps of an oil fallout zone the size of Rhode Island. Valentine described finding a “giant bull’s-eye around the rig, going 25 miles in any direction.”

The investigation gave him access to tremendous resources for studying how much stuff sank down from the ocean surface into the formidable depths, introducing him to a newfound facet of his life’s mission: studying the impact of pollution events on the ocean. 

Long story short, Valentine was inducted into the “spill world,” the often-mysterious field of deep-sea contamination, where his exploration led to the discovery of a massive DDT dump site in 2011.

Valentine was in the midst of piecing together the Deepwater Horizon oil fallout when his attention was first drawn to the Montrose controversy. He became interested in the deliberate dumping of hazardous materials, particularly DDT, off the California coast. 

DEEP-SEA DDT:  Using a remote-controlled robot, Valentine and his team captured the first images of the barrels resting 3,000 feet below the water’s surface off the L.A. coast. Sediment samples they collected from the surrounding seafloor contained concentrations of DDT 40 times worse than DDT manufacturer Montrose’s notorious Superfund site in Palos Verdes. | Credit: Courtesy David Valentine

Coincidentally, he had some time to take on a “side project” in 2011, while doing work on research vessels offshore of L.A. Using an autonomous deep-sea robot, Valentine’s team sought to explore the dumpsite near Catalina.

It was around the Santa Monica and San Pedro basins, which housed some of the 14 legal dump sites (1930s–’70s) of domestic, industrial, and military waste at deep-water locations off the coast of Southern California, according to the Environmental Protection Agency (EPA).

Alongside chemical wastes, other wastes disposed of in the water included oil drilling wastes, refuse and garbage, military explosives, and radioactive wastes. Very little is known about the history of this deep-ocean disposal, the nature of the wastes, or waste sources, the EPA says. 

Valentine’s acoustic measurements produced a high-resolution depiction of the seafloor’s topography, revealing a constellation of little dots, a pattern of a “whole bunch of somethings down there,” Valentine said. 

“They looked like weird little hills. We didn’t really know.”

They returned a couple of days later to take pictures, creating a giant photomosaic strip, which is when they discovered the barrels — what looked like 55-gallon waste drums, weighed down with a layer of concrete and wrapped in chicken wire. As they looked at the images, it became increasingly obvious the barrels were dumped there.

“This wasn’t just, like, somebody’s 55-gallon drum that fell overboard; this was systematic,” Valentine explained. 

Returning with a remotely operated vehicle equipped with robotic arms, they conducted sediment sampling. “We sent it down into this area that’s, like, boom — there’s a barrel,” he said. One barrel after another, they collected the samples.

The investigation revealed alarming levels of DDT and trace amounts of a potentially even more hazardous compound than DDT (but still very understudied), as well as what Valentine described as some other “residual crud.”

“One of the samples we looked at had exceptionally high amounts of DDT, but it also had a bunch of petroleum products,” he said. “So we think that Montrose was not the only company that was dumping.

“We’re trying to develop the basic tools and approaches to begin to actually study these other contaminants of concern in those DDT mixtures,” Valentine continued. “We’re trying to understand the environmental side of this class of molecules.”

DATA DIVE:  The Autonomous Underwater Vehicle Sentry is an autonomous robot that flies around the ocean on a predetermined mission plan and collects data. | Credit: Courtesy David Valentine

Years of dedicated work culminated in a research paper published in the journal Environmental Science & Technology in January 2019, with one of Valentine’s PhD students, Veronika Kivenson, as the lead author. 

“It didn’t get noticed at all. Nobody picked it up,” Valentine said. “We didn’t put out a press release, because I wanted to make sure we got the right coverage.”

Instead, they went to journalist Rosanna Xia, who gave the story its well-deserved deep dive and published it shortly before the 2020 presidential election. Xia’s story, which appeared on the cover of the Los Angeles Times, triggered a media frenzy.

Finally, people started paying attention. Before the story, Valentine struggled to convince state and federal agencies, including the Environmental Protection Agency, to really care.

“She put out her story, and then it exploded into a lot of public interest, to the point where I’ve gotten to brief senators and spend time in Washington, D.C., telling policymakers about it,” Valentine added. 

But even as the saga evolves, it still isn’t clear exactly how much of those chemicals are down there.

A Chemical History

Initially, Montrose released a substantial portion of its chemical waste on its premises, destroying the drains and damaging California’s wetlands, Valentine explained. 

“Then, later, they got in a bit of trouble for that,” he said. “So they started putting it in the sanitary sewer. Basically, flushing it down the toilet.” 

Following its passage through sewage treatment facilities, the acid waste found its way into the Palos Verdes Shelf, the shallow waters hugging the coastline. The consequences were grave — widespread contamination of the shelf area — marking a new chapter in the infamous DDT narrative.

Legal action was taken against Montrose and other liable entities by the state and federal governments in 1990, resulting in a multimillion-dollar settlement in the early 2000s dedicated to DDT cleanup and ocean restoration. This settlement, one of the nation’s largest payouts for a natural resource case, according to the L.A. Times, addressed decades of Montrose’s discharge. 

A groundwater treatment facility at the former Montrose property. | Credit: EPA

From 1947 to 1971, the corporation discharged 800 to nearly 2,000 tons of DDT and toxic PCBs into Los Angeles County sewers and 500,000 barrels (in this case, a unit of volume, equivalent to roughly 42-55 gallons) more into the ocean near White Point. At least 100 tons of DDT remain spread across the Palos Verdes Shelf.

Montrose made an almost-comical attempt at plausible deniability — attributing the presence of DDT in local birds and fish to old farm runoff — and argued that the DDT was naturally degrading, posing little harm to marine life and people. In 1996, the EPA designated the affected region as a Superfund site, reserved for sites contaminated by hazardous substances.

Concentrations of DDT and PCBs remained at alarming levels in fish sold in Los Angeles markets, with species such as the white croaker having been found with tumors presumably linked to chemical exposure.

Mitigation efforts included public campaigns and funding for outreach initiatives to prevent the catch and consumption of contaminated fish. While millions from the settlement contributed to DDT-related projects and ecological restoration, not much has been done to actually “clean up” the toxins, despite past EPA proposals to “cap” the affected area with sand (it’s debatable how and if that could even be done successfully). 

Though fish remain tainted, the EPA’s 2019 review suggested a possible reduction in shelf concentrations, and local bird populations have tentatively rebounded. In September 2022, the Southern California Coastal Water Research Project initiated a 13-month study to measure DDT leaching from sediment along the Palos Verdes Shelf. The project involves passive samplers to gauge DDT and PCB levels leaching into the water column above.

“The chemicals can continue to exert toxic effects for decades,” the project’s press release states. 

Officials, now, are leaning toward just letting nature take its course, crossing their fingers that the chemicals will degrade over time. 

However, some settlement funds went to the National Oceanic and Atmospheric Administration (NOAA) to rehabilitate the marine ecosystem, including restoring 32 acres of reef habitat impacted by the toxins. Nonetheless, the toxins remain on the shelf, even after years of studies and meetings around the issue. 

A Cancerous Cocktail 

Most Californians know of the Proposition 65 “WARNING” signs that are everywhere — Disneyland, parking garages, hotels, fast-food places — and say, “This [noun] has chemicals known to the state of California to cause cancer and birth defects or other reproductive harm.” Well, DDT is on that long list of chemicals that can, in one way or another, seriously screw us up. 

And it’s not just us. Remember the sea lion junk? In addition to that, significant amounts of DDT-related compounds have accumulated in endangered California condors and local dolphin populations. It moves up the food chain, where we, and other predators, sit at the top.

DDT + STDS:  Valentine says the nightmarish combination of herpes and toxic chemicals such as DDT and PCBs is “goo-ifying the junk” of male sea lions. | Credit: Paul Wellman (file)

DDT can build up in fat, and it doesn’t dissolve well in water. Valentine explained that biomagnification — when the chemical accumulates in increasing concentrations as it moves up the food chain — spells intensified effects in animals that eat marine life.

Coastal bird populations have long been threatened by DDT. High levels of DDT in California condors correlate with eggshell thinning, jeopardizing hatchlings’ survival. In the past, DDT pollution led to the near-disappearance of eagles, falcons, and pelicans on the Channel Islands.

The phenomenon inspired “silent spring,” a term coined in 1962 by marine biologist Rachel Carson to illustrate the disquieting silence resulting from declining bird populations.

A recent study published in the journal Ornithological Applications found that hatch success for coastal female California condors was lower than inland populations, presumably due to exposure to DDT-related chemicals (DDE) from feeding on marine animals.

Through monitoring condor nests, Dr. Estelle Sandhaus, Santa Barbara Zoo’s director of conservation and research, was able to compare eggshells between marine-mammal-fed condors from the Central Coast and Southern California condors that rely on terrestrial prey. Condors eating marine mammals along the coast had observably higher rates of eggshell thinning. 

DDT-related compounds have accumulated in endangered California condors populations. | Credit: Courtesy

“We were able to document the loss of the crystalline layer, the outer porcelain layer in the eggshell,” Sandhaus said. “It was missing in these marine-feeding birds. Definitely problematic.”

Likewise, Southern California’s bottlenose dolphins have higher DDT levels than any other dolphin population, reaching as high as 2,000 parts per million (ppm). Many dolphins bearing elevated DDT-related compounds in their blubber have been discovered lifeless on beaches.

“We don’t really know what it’s doing to their mortality at this point, but it’s a major concern,” Valentine said. 

“A dolphin can’t fill out a questionnaire,” he continued. “And the big concern with DDT is mainly developmental. Compounds like DDT can mimic other natural compounds, but they can’t really be destroyed very easily, and so they can really mess with developmental processes that can lead all sorts of bad directions.”

A Grim Reality

What Valentine’s early work showed was that Montrose, and presumably other companies, had another dumping mode: loading up tanks full of waste and pouring it straight into the water.

When DDT is manufactured, it creates sulfuric acid waste, which is so potent it can’t just be dumped in the sewer or storm drain. Instead, Montrose would load the waste into massive tanks. They hired a company called California Salvage, which would dock at the Port of Los Angeles, to transfer the waste onto a barge, then haul it out to sea and pump it overboard around 10 miles away from Catalina Island. 

“We don’t really know how much DDT was mixed in the acid waste — maybe half a percent, or one percent, or even 2 percent,” Valentine said. “And some sort of sludgy, particle-y stuff. And they were making around 10,000 gallons a day and taking it offshore and dumping it.”

In subsequent years after their initial discovery, Valentine’s team conducted extensive research, unearthing a concentration of DDT 40 times worse than the notorious Superfund site in Palos Verdes.

That’s the history researchers have been uncovering, piece by piece. 

The images of rusty barrels resting on the ocean floor off the coast of Los Angeles captured global attention, with both Valentine and fellow researchers initially speculating that the barrels were loaded with DDT. However, later evidence pointed toward the bulk disposal of DDT waste from maritime vessels onto the seafloor — not contained in barrels — according to Valentine’s investigative summary by USC Sea Grant, the project administrator.

The summary states that recent findings suggest the “short-dumping” of DDT and other chemicals between the California mainland and legal dumpsites in the San Pedro and Santa Monica basins, expanding the scope of contamination. The study aims to determine the amounts, locations, and impacts of “DDT+” (DDT plus additional chemicals) in the deep ocean to underpin the assessment and mitigation of risks to environmental and human health. 

[Click to enlarge] SEAFLOOR SAMPLING:Above is a map of Valentine’s sampling stations, which he and his team visited back in March. They sampled the seafloor at each of those locations to help them understand the extent of DDT contamination between L.A. and Catalina. Results are pending. | Credit: Courtesy David Valentine

Right now, Valentine and other researchers are trying to map out where the harmful products are, going off of “sketchy information” (e.g., shipping records) from the 1940s and ’50s. Over recent months, Valentine’s team has meticulously sifted through historical records to supplement detailed sample collection.

Earlier this year, they obtained nearly 100 mud samples from the ocean floor, dividing them into 1,000 subsamples to consider depth and spatial differences. They created a grid pattern spanning suspected bulk-dumping zones across the deep ocean.

Valentine explained, “The first order of business is trying to create a two-dimensional map of where these materials actually sit today. You know, where’s the DDT? And then, if we have enough funding, turning that into a three-dimensional map, looking more into the seafloor to really understand how much of each of the chemicals there is and how they relate to each other.

“We’re trying to understand what happens to these residues on the seafloor. So, 50, 60, 70 years later, how much can be degraded in that time? How does that change with the nuance of the environment?”

THE DREGS: Valentine and his students’ fieldwork includes collecting sediment samples from the ocean floor. | Credit: Courtesy David Valentine

The Scripps Institute of Oceanography has undertaken similar survey efforts, working collaboratively with Valentine and other partners. A preliminary sonar-mapping project by Scripps in 2021 identified more than 27,000 barrel-like objects, and more than 100,000 total debris objects, on the seafloor. 

Multiple federal and state agencies, led by the EPA, are also collaborating to study the contamination present at Dumpsite 2, and are looking into whether, and how, that cocktail of chemicals is creating risks to the environment or to human health.

In the meantime, the EPA has assured that the disposal site is approximately 3,200 feet below the water’s surface, so it is unlikely that water-goers are recreating near the site.

Senator Dianne Feinstein, who recently announced her retirement, pushed for Congress to support the work being done by researchers and wrote letters to both the EPA and the NOAA to ask what could be done. Congress allocated $5.6 million to advance the research, which was matched by Governor Gavin Newsom. USC Sea Grant and the state supplemented this with an additional $5.2 million, ensuring 18 more months of research — what Valentine is working on now.

Feinstein, Valentine recounted, was not a hard sell. “She actually contacted us,” he added. “When she saw the coverage on it, she was so angry. One of her final priorities is that she wants to see it fixed. But, you know, we can figure out what the problem is, but we are a long way away from the fix.”

In terms of solutions, they’re still in the early stages. The extent of the contamination remains uncertain, and routes of ecosystem exposure are not well-understood. Still, Valentine’s team is delving into microbiology, as certain microbes can degrade DDT. 

“They’re not doing a very good job in these natural settings right now,” he lamented. “But we want to get to know them, understand how they’re doing it.”

Amid recurring bad news, Valentine somehow manages to maintain a healthy mindset. He admitted, “I’ve been so immersed in it for so long that I don’t often sit and ponder the existential side of it. I’m so busy trying to understand what happened and where it’s all going that I don’t spend as much time on that side of it. I guess that’s how I deal with it.”

A Home Base in Santa Barbara

Valentine’s career isn’t all DDT and sea lion cancer. He’s been working on a hoard of different projects simultaneously. If you try to reach him, don’t be surprised if you get an out-of-office message in return saying he’s on an “oceanographic expedition.” 

Recently, he could be found working off the coast of Santa Barbara with his UCSB lab group, conducting daily dives with the submersible Alvin, plus autonomous robotic operations at night.

Despite his regular sea adventures, the San Diego–born, Davis-raised 50-year-old has put down roots in Santa Barbara and started a family here. He hosts Dos Pueblos High School debate team sessions for his daughter, regularly attends his children’s volleyball tournaments, and volunteers with organizations like the Goleta Valley Historical Society.  

LIKE FATHER: Valentine’s middle daughter joined him and his students for a sampling trip in December 2022. | Credit: Courtesy David Valentine

He signed on the dotted line for a faculty job at UCSB in 2001 and started teaching in 2002, working there longer than he’s worked anywhere else. 

Now, he runs a lab with about 20 students, a quarter of whom are working on the DDT projects. But even as DDT takes up a big piece of the pie, he’s juggling around 10 other projects simultaneously. Some are high-profile, and some are random side projects — encompassing everything from a study funded by the Department of Energy on carbon-dioxide reduction approaches using kelp to experimenting with different biofuels. 

“From student to chancellor, UCSB is a great place to do marine research,” Valentine said. “I think we somehow attract people here because they care about the ocean, which is a great thing. 

“It’s easy to find students excited by it, and students will find me. Actually, my biggest financial supporters are our alumni. When you’re trying to do things that are kind of out of the box, it helps to have that support.”

But money, Valentine explained, is only one small piece of the puzzle. 

“I went into what I do because I love the discovery,” he said. “Can I do something that’s actually impactful and can ultimately help people or society? But also, for myself, can I discover things that nobody knew before? That’s really what kept me in science and why I didn’t go into business or something and make a lot more money.”

FIELDWORK: Valentine is seen here with a group of students and postdoctoral scholars on a research vessel, many of whom were enrolled in a class that Valentine was teaching about field studies in marine science. | Credit: Courtesy David Valentine

A Major Development 

This coming fall, 11 years of work will come to fruition as UCSB welcomes its inaugural cohort for the new marine science major, a program crafted by Valentine himself. Despite the school’s coastal location and although it is home to a Marine Science Institute, UCSB had not offered an official marine science major until now; the closest equivalent was an aquatic biology major.

Earlier this year, the program hired its first faculty members and hosted its first student recruitment weekend in April. “That’s the first time I ever had to put on a horse-and-pony show for parents,” Valentine chuckled. “It’s kind of crazy.”

The marine science major will be housed within the College of Creative Studies, which makes up only about 2 percent of the campus population. Valentine’s aim is to have a modest enrollment of around 50 students to allow for early engagement in lab work, even in students’ freshman year. 

“I didn’t want it to be this massive, sprawling thing,” Valentine said. “It allows it to be a little bit of a different major, where it can be very research-focused, and without a lot of the firm requirements of a traditional major in the College of Letters and Science.”

The journey to finally welcoming an incoming cohort took a lot of effort.

Credit: Ingrid Bostrom

Valentine recounted his participation in the Aldo Leopold Leadership Program in 2013, where he underwent visioning exercises to help him look inward and pinpoint what he wanted to accomplish. They asked him to find one thing to prioritize working toward over a period of five years. “I’m more on the three-things-over-15-years plan,” he said. 

One of those things, “biological propane,” is not going so well, Valentine admitted. “It’s still happening, just slowly. So let’s go for two for 15 years.”

Another was the marine science major, which Valentine initially anticipated to take only a few years. He laughed, though, saying that “11 years later, I met my first student.”

But the top of his list was advancing the DDT project beyond the risk of it being buried in literature so that they could actually start doing something about it. 

“I needed to have the story. I needed the story to be far enough along that it wasn’t just like, ‘Oh, hey, okay, there’s DDT in the ocean.’ I wanted to have enough to really know what I was talking about and have suggestions,” he emphasized.

He wanted to be careful, too, about how the story was told, to be realistic and accurate while avoiding sensationalism.

“There’s nothing worse, I think, than dramatically overblowing a story. And then suddenly, it’s worse than global warming,” he said. “This is bad, and we have to understand it, but we have to put it in the scheme of everything else that’s bad.

“But, you know, part of me was just glad that it was finally out of my hands and for the rest of the world to make a decision on.” 

Credit: Ingrid Bostrom


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