It’s not just toxic chemical waste and mysterious barrels littering the seabed off the coast of Los Angeles. Oceanographers have now discovered what appears to be a huge dumping ground of military weaponry.
As part of an unprecedented effort to map and better understand the history of ocean dumping in the region, scientists have found a large number of discarded ammunition boxes, smoke floats and depth charges lurking 3,000 feet underwater. Most appear to date from the World War II era and it remains unclear what risk they may pose to the environment.
“We started finding the same objects consistently by the dozens, if not hundreds… It actually took a few days to really understand what we were seeing on the seafloor,” says Eric Terrill, who, along with Sophia Merrifield of the Scripps Institution of Oceanography from UC San Diego. “Who knew that in our backyard: the more you look, the more you find.”
Among the munitions documented were Hedgehog and Mark 9 depth charges – explosives typically dropped from warships to attack submarines. Researchers also identified Mark 1 smoke rafts: chemical smoke munitions dropped by ships to mark locations or conceal their movements.
These findings, made public Friday, build on a stunning 2021 sonar survey that identified tens of thousands of barrel-shaped objects between Los Angeles and Catalina Island. The research team of Merrifield and Terrill, aided by a rare collaboration with the US Navy Supervisor of Salvage, set out again last year – this time with even more advanced sonar technology, as well as a high-definition deep-sea camera that attempted to visually identify as many objects as possible.
Disposing of military waste at sea has not been uncommon in recent decades, but this once-forgotten history of dumping into the ocean continues to haunt our environment to this day. (A World War II practice bomb even washed up in Santa Cruz County last week after a particularly high tide.)
The US Navy confirmed that what the Scripps team discovered “is likely the result of World War II disposal practices” and noted in a statement that “the disposal of munitions at sea at this location was approved at the time to ensure safe disposal when Navy ships returned to U.S. port.” Officials are now reviewing Scripps’ latest findings and “determining the best path forward to ensure the risk to human health and the environment is appropriately managed.”
Public interest in Southern California’s legacy of ocean dumping has increased since the Los Angeles Times reported that as many as half a million barrels of acidic DDT waste had gone missing in the deep ocean, according to old ship logs and a UC Santa Barbara study that provided the first real glimpse into how the Los Angeles coast became an industrial dumping ground.
Dozens of marine scientists and ecotoxicologists have since met regularly to discuss the data gaps in our understanding of DDT, a pesticide (banned in 1972) that was largely manufactured in Los Angeles and was so powerful that it poisoned birds and fish. Congress — at the urging of U.S. Sen. Alex Padilla (D-Calif.) and the late Sen. Dianne Feinstein (D-Calif.) — has appropriated more than $11 million to work on the issue, and Governor Gavin Newsom has also given an impetus. research with another $5.6 million.
In another recent plot twist, an extensive historical investigation by the U.S. Environmental Protection Agency concluded that the pesticide waste was not actually contained in barrels, but that the chemicals were poured directly into the ocean from huge tankers. While digging up old records, the EPA also discovered that between the 1930s and early 1970s, thirteen other areas off the coast of Southern California had also been approved for dumping military explosives, radioactive waste, and various refinery byproducts – including 3 million tons of petroleum waste.
Read more: The history of DDT dumping into the ocean off the coast of LA is even worse than expected, EPA finds
“When the deepwater deposit was first discovered in more detail by the UC Santa Barbara team, the response was, ‘Oh my god, this is the tip of the iceberg.’ And now we see how big this iceberg is – we still don’t even know how big it is,” said Mark Gold, an environmental scientist at the Natural Resources Defense Council who has worked on the DDT problem since the 1990s.
“What’s scary – as if it had to be more scary – is that we have over 100 square miles of contamination in this landfill, with high DDT concentrations at depths no one has ever looked at before. I also saw all the other stuff being dumped,” he said. “And it’s just what we’re seeing, from a major munitions standpoint, as opposed to, how do we know that there haven’t been other chemicals dumped by the Department of Defense?”
David Valentine, the UC Santa Barbara scientist whose marine research team first encountered dozens of terrifying-looking barrels, also emphasized that the less visible pollution is more of a cause for concern. The legacy of DDT contamination still haunts sea lions and dolphins in mysterious ways, and fellow researchers have traced high levels of the perennial chemical all the way up the marine food chain to critically endangered condors.
Read more: Scientists discover surprising concentrations of pure DDT along the seafloor off the coast of LA
“We can’t lose sight of the 500-pound gorilla down there, the enormous amounts of chemical waste dumped and spread everywhere,” said Valentine, noting that the contents of the barrels his team discovered are still there. a mystery.
“Now that we know that the military had done its thing and that the chemical dumps were dumped in bulk, the question becomes: What else could have been needed to contain these barrels?” he said.
Valentine, who has also worked with a number of scientists to summarize how DDT might remobilize from the seafloor, added that the latest high-resolution imaging from Scripps is instrumental in helping the entire research community understand how the seafloor actually looks. looks.
The deepest parts of the seafloor between Los Angeles and Catalina Island had never before been mapped in this way. Locating specific objects on such a wide stretch of seabed has been likened to looking for the smallest needles in the largest haystack.
During the most recent expedition, a crew of nine Scripps researchers and 10 specialists from the Navy’s Supervisor of Salvage scanned the seafloor for more than 300 hours, capturing as many images as possible with high-resolution technology typically unavailable to scientists.
Patterns started to emerge. Object after object came into view and the scientists had to process and interpret an overwhelming amount of data live.
Terrill, an oceanographer who, as co-founder of the nonprofit Project Recover, also specializes in scouring the deep sea for downed military aircraft, enlisted an underwater archaeologist on his team to help identify the vintage military debris.
Another surprise for researchers was the discovery of dozens of whale skeletons and carcasses, known as whale traps. Advanced sonar measurements have identified potentially more than 60 whale falls, and researchers were able to visually confirm seven of them with their camera system.
Craig Smith, professor emeritus of oceanography at the University of Hawaii who has devoted much of his life to studying whale falls, noted that this finding is particularly groundbreaking in his field. Only about 50 naturally occurring whale falls have ever been identified around the world, so just locating another 60 off the coast of Los Angeles effectively doubles the number of known whale falls.
Many questions remain about why there appears to be such a high concentration of dead whales slowly decomposing off the coast of Southern California. Smith and his colleagues would like to study this further.
“If we do population-level calculations, we estimate that there are approximately 600,000 or more whales in the world ocean. But they fall more or less randomly, so they’re hard to find,” said Smith, noting that whale falls become fascinating but elusive ecosystems for deep-sea critters.
Merrifield, the physical oceanographer who co-led the Scripps expedition, noted that a vast amount of new data remains to be refined and analyzed. For example, her team was able to capture high-resolution images of various seafloor textures, as well as mounds that could indicate small burrowing animals that could stir up chemicals half-buried in the sediment.
“New technologies are really changing the way we look at the seabed, and there are interdisciplinary problems, from microbiology and remediation, to chemistry, to geology, to physical oceanography and transport, that require all kinds of specialists to come together,” she said . “I hope the takeaway here is that we may not have found what we thought we were going to find, but we found a lot of really important objects and insights that will hopefully lead to really good scientific results for the community.”
This story originally appeared in the Los Angeles Times.