For decades, a graveyard of corroding barrels has littered the seafloor
just off the coast of Los Angeles. It was out of sight, out of mind � a
not-so-secret secret that haunted the marine environment until a team of
researchers came across them with an advanced underwater camera.

Speculation abounded as to what these mysterious barrels might contain.
Startling amounts of DDT near the barrels pointed to a little-known
history of toxic pollution from what was once the largest DDT manufacturer
in the nation, but federal regulators recently determined that the
manufacturer had not bothered with barrels. (Its acid waste was poured
straight into the ocean instead.)

Now, as part of an unprecedented reckoning with the legacy of ocean
dumping in Southern California, scientists have concluded the barrels may
actually contain low-level radioactive waste. Records show that from the
1940s through the 1960s, it was not uncommon for local hospitals, labs and
other industrial operations to dispose barrels of tritium, carbon-14 and
other similar waste at sea.

�This is a classic situation of bad versus worse. It�s bad we have
potential low-level radioactive waste just sitting there on the seafloor.
It�s worse that we have DDT compounds spread across a wide area of the
seafloor at concerning concentrations,� said David Valentine, whose
research team at UC Santa Barbara had first discovered the barrels and
sparked concerns of what could be inside. �The question we grapple with
now is how bad and how much worse.�

This latest revelation from Valentine�s team was published Wednesday in
Environmental Science & Technology as part of a broader, highly
anticipated study that lays the groundwork for understanding just how much
DDT is spread across the seafloor � and how the contamination might still
be moving 3,000 feet underwater.

Public concerns have intensified since The Times reported in 2020 that
dichlorodiphenyltrichloroethane, banned in 1972 following Rachel Carson�s
�Silent Spring,� is still haunting the marine environment in insidious
ways. Scientists continue to trace significant amounts of this decades-old
�forever chemical� all the way up the marine food chain, and a recent
study linked the presence of this once-popular pesticide to an aggressive
cancer in California sea lions.

Dozens of ecotoxicologists and marine scientists are now trying to fill
key data gaps, and the findings so far have been one plot twist after
another. A research team led by UC San Diego�s Scripps Institution of
Oceanography just recently set sail to help map and identify as many
barrels as possible on the seafloor � only to discover a multitude of
discarded military explosives from the World War II era.

And in the process of digging up old records, the U.S. Environmental
Protection Agency discovered that from the 1930s to the early 1970s, 13
other areas off the Southern California coast had also been approved for
dumping of military explosives, radioactive waste and various refinery
byproducts � including 3 million metric tons of petroleum waste.

Here�s what we know about the legacy of DDT dumping off L.A.�s coast
DDT was banned 50 years ago, but its toxic legacy continues to affect the
California marine ecosystem and threaten various animal species.

May 6, 2024

In the study published this week, Valentine found high concentrations of
DDT spread across a wide swath of seafloor larger than the city of San
Francisco. His team has been collecting hundreds of sediment samples as
part of a methodical, large-scale effort to map the footprint of the
dumping and analyze how the chemical might be moving through the water and
whether it has broken down. After many trips out to sea, they still have
yet to find the boundary of the dump site, but concluded that much of the
DDT in the deep ocean remains in its most potent form.

Further analysis, using carbon-dating methods, determined that the DDT
dumping peaked in the 1950s, when Montrose Chemical Corp. of California
was still operating near Torrance during the pesticide�s postwar heyday �
and prior to the onset of formal ocean dumping regulations.

Clues pointing to the radioactive waste emerged in the process of sorting
through this DDT history.

Jacob Schmidt, lead author of the study and a PhD candidate in Valentine�s
lab, combed through hundreds of pages of old records and tracked down
seven lines of evidence indicating that California Salvage, the same
company tasked with pouring the DDT waste off the coast of Los Angeles,
had also dumped low-level radioactive waste while out at sea.

The company, now defunct, had received a permit in 1959 to dump
containerized radioactive waste about 150 miles offshore, according to the
U.S. Federal Register. Although archived notes by the U.S. Atomic Energy
Commission say the permit was never activated, other records show
California Salvage advertised its radioactive waste disposal services and
received waste in the 1960s from a radioisotope facility in Burbank, as
well as barrels of tritium and carbon-14 from a regional Veterans
Administration hospital facility.

Given recent revelations that the people in charge of getting rid of the
DDT waste sometimes took shortcuts and just dumped it closer to port,
researchers say they would not be surprised if the radioactive waste had
also been dumped closer than 150 miles offshore.

�There�s quite a bit of a paper trail,� Valentine said. �It�s all
circumstantial, but the circumstances seem to point toward this company
that would take whatever waste people gave them and barge it offshore �
with the other liquid wastes that we know they were dumping at the time.�

Ken Buesseler, a marine radiochemist who was not affiliated with the
study, said that generally speaking, some of the more abundant radioactive
isotopes that were dumped into the ocean at the time � such as tritium �
would have largely decayed in the past 80 years. But many questions remain
on what other potentially more hazardous isotopes could�ve been dumped.

The sobering reality, he noted, is that it wasn�t until the 1970s that
people started to take radioactive waste to landfills rather than dump it
in the ocean.

He pulled out an old map published by the International Atomic Energy
Agency that noted from 1946 to 1970, more than 56,000 barrels of
radioactive waste had been dumped into the Pacific Ocean on the U.S. side.
And across the world even today, low-level radioactive waste is still
being released into the ocean by nuclear power plants and decommissioned
plants such as the one in Fukushima, Japan.

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In a 1999 report by the International Atomic Energy Agency titled
�Inventory of radioactive waste disposals at sea,� a grainy map shows that
at least 56,261 containers of radioactive waste were dumped into the
Pacific Ocean from 1946 to 1970. (International Atomic Energy Agency)
�The problem with the oceans as a dumping solution is once it�s there, you
can�t go back and get it,� said Buesseler, a senior scientist at Woods
Hole Oceanographic Institution and director of the Center for Marine and
Environmental Radioactivity. �These 56,000 barrels, for example, we�re
never going to get them back.�

Mark Gold, an environmental scientist at the Natural Resources Defense
Council who has worked on the toxic legacy of DDT for more than 30 years,
said it is unsettling to think just how big the consequences of ocean
dumping might be across the country and the world. Scientists have
discovered DDT, military explosives and now radioactive waste off the Los
Angeles coast because they knew to look. But what about all the other dump
sites where no one�s looking?

�The more we look, the more we find, and every new bit of information
seems to be scarier than the last,� said Gold, who called on federal
officials to act more boldly on this information. �This has shown just how
egregious and harmful the dumping has been off our nation�s coasts, and
that we have no idea how big of an issue and how big of a problem this is
nationally.�

U.S. Sen. Alex Padilla (D-Calif.) and Rep. Salud Carbajal (D-Santa
Barbara), in a letter signed this week by 22 fellow members of Congress,
urged the Biden administration to commit dedicated long-term funding to
both studying and remediating the issue. (Congress has so far allocated
more than $11 million in one-time funding that led to many of these
initial scientific findings, and an additional $5.2 million in state
funding recently kicked off 18 more months of research.)

�While DDT was banned more than 50 years ago, we still have only a murky
picture of its potential impacts to human health, national security and
ocean ecosystems,� the lawmakers said. �We encourage the administration to
think about the next 50 years, creating a long-term national plan within
EPA and [the National Oceanic and Atmospheric Administration] to address
this toxic legacy off the coast of our communities.�

As for the EPA, regulators urged the growing research effort to stay
focused on the agency�s most burning questions: Is this legacy
contamination still moving through the ocean in a way that threatens the
marine environment or human health? And if so, is there a potential path
for remediation?

EPA scientists have also been refining their own sampling plan, in
collaboration with a number of government agencies, to get a grasp of the
many other chemicals that had been dumped into the ocean. The hope, they
said, is that all these research efforts combined will ultimately inform
how future investigations of other offshore dump sites � whether along the
Southern California coast or elsewhere in the country � could be
conducted.

�It�s extremely overwhelming. � There�s still so much we don�t know,� said
John Chesnutt, a Superfund section manager who has been leading the EPA�s
technical team on the ocean dumping investigation. �Whether it�s
radioactivity or explosives or what have you, there�s potentially a wide
range of contaminants out there that aren�t good for the environment and
the food web, if they�re really moving through it.�

https://www.latimes.com/environment/story/2024-02-21/radioactive-waste-
ocean-dumping-los-angeles-coast