The scale of the problem only really came into public view recently. In 2020, an investigation by the Los Angeles Times<\/a> revealed that deep-sea surveys had uncovered large numbers of barrels scattered across the ocean floor. Follow-up missions by the Scripps Institution of Oceanography later identified around27,000 barrel-like objects and more than100,000 pieces of debris.<\/p>\n Alkaline Waste As The Main Suspect<\/p>\n For years, scientists suspected that many of these barrels <\/a>contained DDT, a now-banned pesticide heavily linked to contamination in the region. Yet new sediment analyses suggest otherwise.<\/p>\n Findings published in PNAS Nexus <\/a>show that researchers led by microbiologist Johanna Gutleben<\/a> detected no increase in DDT concentrations near sampled barrels. Instead, three barrels surrounded by visible white halos showed extremely high pH levels of around 12 in nearby sediments.<\/p>\n This points to the presence of caustic alkaline waste rather than pesticide residues. In a statement relayed by Scripps Institution of Oceanography<\/a>, Gutleben noted that:<\/p>\n \u201cUp 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.\u201d\u00a0<\/p>\n The exact chemical composition remains unidentified, though the study notes that both DDT production and oil refining can generate alkaline byproducts.<\/p>\n White Halos Expose Extreme Chemistry Hotspots<\/p>\n The unusual white rings observed around many barrels have now been explained through chemical reactions triggered by leaking waste. The study describes how the alkaline material reacts with magnesium in seawater to form brucite, a mineral that creates a crust-like layer. Over time, this mineral dissolves, maintaining high alkalinity in the sediment and driving further reactions that produce calcium carbonate deposits, visible as pale halos.<\/p>\n These halos are more than just visual markers. They signal zones where chemical conditions have been drastically altered. Researchers estimate that roughly one-third of observed barrels display such features.<\/p>\n Marine Life Near Breaking Point<\/p>\n Sediment samples taken near the barrels with those white halos showed very little microbial DNA, which suggests most organisms just can\u2019t survive in such an alkaline environment. Researchers did find a few specialized bacteria, similar to ones that live in deep-sea hydrothermal vents<\/a>oralkaline hot springs. These microbes <\/a>are built for extreme conditions, but they only make up a tiny fraction of marine life.<\/p>\n![\"Deep](\"https:\/\/www.newsbeep.com\/us\/wp-content\/uploads\/2026\/04\/Deep-sea-barrels-off-Los-Angeles-some-surrounded-by-white-halos-caused-by-leaking-alkaline-waste-120.webp\")
Deep-sea barrels and their halos highlight areas of extreme chemical conditions. Credit: PNAS Nexus<\/p>\n![\"Map](\"https:\/\/www.newsbeep.com\/us\/wp-content\/uploads\/2026\/04\/Map-showing-the-known-offshore-dumpsite-and-seafloor-survey-area-off-the-coast-of-Los-Angeles-near-t.webp\")
Map showing the known offshore dumpsite and seafloor survey area off the coast of Los Angeles near the Palos Verdes Peninsula. Credit: Scripps Institution of Oceanography<\/p>\n