| masraum |
09-18-2025 01:11 PM |
Crazy things "we" did to the planet in the past
It's amazing what "we" thought was OK back in the day. I guess this isn't much different than the old thing that we've all seen that says that you can dig a hole and fill it with gravel so you can just dump your used motor oil into a hole in the ground. (of course, oil was much simpler back then, and not, I think, much different from how it was when it got pumped out of the ground, so maybe that was different)
Metal Barrels Dumped Off the Coast of Los Angeles Are Encircled by Mysterious White Halos—and Scientists Think They Finally Know Why
https://www.smithsonianmag.com/smart-news/metal-barrels-dumped-off-the-coast-of-los-angeles-are-encircled-by-mysterious-while-halos-and-scientists-think-they-finally-know-why-180987334/
At least some of the barrels contain caustic alkaline waste, which has made the surrounding ecosystems inhospitable to most life forms, a new study suggests
I'm not sure if this image will work due to the complexity of the link
https://th-thumbnailer.cdn-si-edu.co...lo_trimmed.gif
Quote:
In 2011, scientists made a shocking discovery off the coast of Los Angeles: Corroded metal barrels were resting on the seafloor, including some that were surrounded by eerie white halos in the nearby sediment. They suspected the barrels contained DDT, because the underwater area around them was heavily contaminated with the now-banned toxic pesticide, but they didn’t know for certain.
Now, researchers say they are one step closer to solving the mystery of the barrels’ contents. Recent testing suggests that at least some of the barrels may not contain DDT as previously thought but, rather, some sort of caustic alkaline waste, according to a new study published September 9 in the journal PNAS Nexus.
Need to know: Barrels of waste on the seafloor
When the metal barrels were initially discovered, scientists counted dozens of them. Now, researchers have mapped about 25,000.
The barrels’ exact origins are murky. However, federal records from the Environmental Protection Agency show that from the 1930s to the early 1970s, government agencies allowed companies to dump various types of waste at 14 underwater sites off the coast of Southern California. For those four decades, manufacturers got rid of their refinery waste, filter cakes and oil drilling waste, chemical waste, garbage, military explosives and radioactive waste at these dump sites.
David Valentine, a microbial geochemist at the University of California, Santa Barbara, first stumbled upon the barrels more than a decade ago. But his discovery didn’t receive widespread attention until 2020, when Los Angeles Times reporter Rosanna Xia wrote an investigative story about the long-forgotten dumping grounds. Scientists have been studying the barrels ever since.
Robotic arm taking a sediment sample near a barrel
The researchers took sediment samples near the barrels using a remotely operated underwater vehicle. Schmidt Ocean Institute
For the new study, researchers used a remotely operated underwater vehicle to collect samples of sediment at various distances from five of the barrels, including three that had the white halos. When they analyzed the samples from near the barrels, they found high levels of DDT—but intriguingly, the amount of DDT was roughly the same no matter the distance from the barrels.
Samples from around the containers with halos had high pH levels—around 12, which is almost as basic, or alkaline, as household bleach. These samples also contained very few microbes.
Taken together, the results suggest the containers encircled by halos are full of alkaline waste, rather than DDT.
“DDT was not the only thing that was dumped in this part of the ocean, and we have only a very fragmented idea of what else was dumped there,” says lead author Johanna Gutleben, a microbiologist at the Scripps Institution of Oceanography, in a statement. “We only find what we are looking for, and up to this point, we have mostly been looking for DDT. Nobody was thinking about alkaline waste before this, and we may have to start looking for other things as well.”
As it leached out of the barrels, the alkaline waste appears to have altered the surrounding environment to the point that most life forms could no longer survive there. The scientists did, however, find evidence of a few specially adapted species of microbes, similar to the extremophiles found living in deep-sea hydrothermal vents and alkaline hot springs.
“There shouldn’t be these extreme habitats out there in that part of the ocean, and that’s affecting not only the microbes, but the animals and all the way up the food chain, and who knows what else,” says co-author Paul Jensen, a retired marine microbiologist at the Scripps Institution of Oceanography, to the San Diego Union-Tribune’s Maura Fox.
The halos likely formed when the leaking alkaline waste reacted with magnesium in the ocean water. This interaction produced the mineral brucite, which formed a hard crust in the sediment around the barrels. Over time, the brucite is dissolving and producing calcium carbonate, which settles around the barrels as halos.
Scientists were not able to identify the specific alkaline waste substances contained within the barrels. However, they point out that several industrial processes were known to produce alkaline waste, including DDT manufacturing and oil refining, so the barrels might be linked to those.
They also can’t estimate the full extent of the potential alkaline waste contamination. Roughly a third of the barrels identified so far have halos, but they don’t know if that ratio applies to all the barrels on the seafloor. Scientists also don’t know the exact number of barrels, though a previous estimate suggests there are more than 25,000.
“We don’t know how big the problem really is,” Gutleben tells the San Diego Union-Tribune.
One thing seems certain: Given that the barrels were dumped more than 50 years ago and that they’re still having a major impact on the surrounding environment, the chemicals are likely here to stay. They represent a new type of “persistent pollutant” that takes a long time to break down, the researchers write in the paper.
“It could take several thousand years for the effects of caustic alkaline waste dumping in the San Pedro Basin to be resolved,” they add.
Looking ahead, scientists are turning their attention to the broader problem of DDT contamination in the region. Physically removing the contaminated sediment would be nearly impossible and would likely circulate DDT into the surrounding water. Instead, scientists are pinning their hopes on finding microbes that might be able to break down the pollutant.
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