LOS ANGELES－Marine scientists said they have found what they believe to be as many as 27,000 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 145 square kilometers 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 and in the ecosystem.
DDT was widely used on farms as an insecticide before being banned in the United States in 1972.
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. They also were seen beyond the dumpsite limits.
“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 there.
The long-term impact on marine life and humans is still unknown, said Scripps chemical oceanographer and professor of geosciences Lihini Aluwihare.
Diana Aga, a chemistry professor at University at Buffalo who is not affiliated with the study, said the findings were shocking if the barrels are proven to contain the toxic chemical.
Cancer in sea lions
If the barrels haven’t leaked, they could be moved to a place where disposal is safer, Aga said. If they leaked, scientists could take samples from the water and other marine life to gauge the damage.
Scientists conducted the survey from March 10-24 following a Los Angeles Times report last year about evidence that DDT was dumped into the ocean.
High levels of DDT have been detected in the area’s marine mammals, and the chemical has been linked to cancer in sea lions.
The Los Angeles Times reviewed shipping logs from a disposal company supporting Montrose Chemical Corp of California, a DDT-producing company. The logs showed 2,000 barrels of DDT-laced sludge were dumped in the deep ocean each month from 1947 to 1961 off Catalina, and other companies also dumped there until 1972.
Agencies – Xinhua