CFP
Researchers recover an autonomous underwater vehicle after a search for discarded DDT barrels.
Marine scientists say they have found what they believe to be as many as 25,000 barrels that possibly contain DDT dumped off the Southern California coast near Catalina Island, where a massive underwater toxic waste site dating back to World War II has long been suspected.
The 27,345 “barrel-like” images were captured by researchers at the University of California San Diego’s Scripps Institution of Oceanography. They mapped more than 14,400 hectares of seafloor between Santa Catalina Island and the Los Angeles coast in a region previously found to contain high levels of the toxic chemical in sediments.
Historical shipping logs show that industrial companies in Southern California used the basin as a dumping ground until 1972, when the Marine Protection, Research and Sanctuaries Act, also known as the Ocean Dumping Act, was enacted.
Resting deep in the ocean, the exact location and extent of the dumping was not known until now. The territory covered was “staggering,” said Eric Terrill, chief scientist of the expedition and director of the Marine Physical Laboratory at Scripps Institution of Oceanography.
Underwater drones using sonar technology captured high-resolution images of barrels resting 900 meters below the surface all along the steep seafloor that was surveyed.
“It really was a surprise to everybody who’s worked with the data and who sailed at sea,” he told reporters on Monday.
The survey provides “a wide-area map” of the barrels, though it will be up to others to confirm through sediment sampling that the containers hold DDT, Terrill said. It’s estimated between 350 and 700 tons of DDT were dumped in the area, 20 kilometers from Los Angeles, and 12km from Catalina Island.
The long-term impact on marine life and humans is still unknown, said Scripps chemical oceanographer and professor of geosciences Lihini Aluwihare, who in 2015 co-authored a study that found high amounts of DDT and other man-made chemicals in the blubber of bottlenose dolphins that died of natural causes.
(Agencies)