Thousands of industrial waste have been scattered across the seabed off Los Angeles, and have been there for decades, but scientists still don’t fully understand the chemicals that this junkyard is leaking into the environment.
Research now reveals that some of the chemicals leaking from the barrel cemetery have been identified as strong alkaline, the opposite chemical to acidity.
Between the 1930s and the early 1970s, radioactive waste, refinery waste, chemical waste, petroleum waste and military explosives were dropped at 14 dump sites in the deep waters off the coast of Southern California, according to the U.S. Environmental Protection Agency.
This huge underground junk. In 2020, an article from the LA Times came into public consciousness when a deep-sea robotic survey revealed dozens of barrels scattered across the seabed. Subsequently, in 2021 and 2023, a follow-up study by the Scripps Oceanography Institute in California identified approximately 27,000 shapes of the barrel and more than 100,000 total fragmentary objects in the seabed total. Some suspected that much of it was surrounded by whitish halos of sediment, containing the now-destroyed pesticide DDT.
To this day, however, the total number of barrels on the seabed, and what most of them are included, remains unknown.
Johanna Gutlben, a microbiologist at the Scripps facility, and her colleagues revealed the results of sediment samples taken near five barrels in 2021 using remotely controlled vehicles.
Related: Alaska’s rivers become bright orange and as acidic as vinegar.
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The three barrels they checked have white halos around, and because all samples from near these barrels are very high pH (about 12) and very few microorganisms that live there, the team says the barrels contain caustic waste, which can damage organic matter and leach out high concentrations of potentially toxic metals.
The team’s investigation was published on the Journal PNAS Nexus on Tuesday (September 9th).
“Up to this point we were primarily looking for DDT. No one had thought of alkaline waste before this, so we might need to start looking for something else,” Gutleben said in a statement.
Sampling did not specify which specific chemicals were present in the barrel, but DDT manufacturing in particular produces alkaline waste, similar to petroleum refining.
“One of the main waste streams from DDT production was acid and we didn’t put it in the barrel,” Gutleben said. “It makes me wonder. What was more deserving to be put in a barrel than DDT acid waste?”
Researchers say it is likely that alkaline waste has transformed the seabed into an extreme environment, as they discovered very limited levels of microbial DNA near the barrel. However, they found some traces of special bacteria – family species adapted to alkaline environments, such as deep-sea hot water and alkaline hot springs.
The team also discovered how strange halos form. When alkaline waste leaks out of the barrel, it reacts with the magnesium in the water, creating a magnesium hydroxide called bluechate, forming a concrete-like crust. The Bluche then slowly dissolves, leading to a reaction in the surrounding seawater, keeping the sediment high pH. This forms calcium carbonate and settles as white dust around the barrel.
It suggests that alkaline waste has been ongoing for over half a century, suggesting that rather than quickly dissipating in seawater, it should be considered as a lasting contaminant, similar to DDT, which has long-term environmental impacts.
“It’s shocking that you’re still seeing these effects in over 50 years,” he said.
Researchers suggest that white halos can be used to identify which barrels contain alkaline waste and assess the overall degree of contamination. Jensen said about a third of the barrels seen so far have halos, but it is unclear whether this ratio will be retained as more barrels are discovered.
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