Seafloor Mapping Reveals 25,000 Barrels of Waste, Toxic Debris Off Los Angeles Coast

The University of California San Diego's Scripps Institute of Oceanography used robotics to map the seafloor around Los Angeles, finding waste materials.

More than 36,000 acres of the seafloor between the coast of Los Angeles and Catalina Island to the south were mapped by the Scripps project. The area has been previously identified as having high levels of DDT, a toxic chemical, from the sediments recovered from the seafloor.

The Scripps expedition developed together with the NOAA Office of Marine and Aviation Operations and the National Oceanographic Partnership Program, ran for two weeks last March, from the 10th to the 24th. According to a press release from Scripps Institution of Oceanography Monday, April 26, the project is a part of the institute's ongoing collaboration with NOAA's Uncrewed Systems Operations Center.

ALSO READ: Continuing Water Crisis Turns the Santiago River Basin Into a "Slow-Motion Chernobyl"

Dumping Ground for Industrial Waste

The survey conducted onboard the Research Vessel (R/V) Sally Ride found more than 27,000 targets having "high confidence to be classified as a barrel," as well as more than 100,000 different forms of debris on the seafloor.

"Unfortunately, the basin offshore Los Angeles had been a dumping ground for industrial waste for several decades, beginning in the 1930s. We found an extensive debris field in the wide-area survey," explains Eric Terrill, chief scientist of the research expedition as well as the director of Scripps' Marine Physical Laboratory, in the Institute's release.

He adds that they have mapped the area, they are hopeful that the data they gathered would lead to strategies addressing the potential effects of this dumping of industrial wastes.

Scripps also reported that in 2011 and 2013, University of California Santa Barbara professor David Valentine found unusual levels of DDT in the sediments in the same seafloor location. Later efforts also revealed similar levels of toxic chemicals in marine mammals like sea lions and dolphins, which is believed to have led to the development of cancer among seals.

Long-Time Practice of Poisoning the Seafloor

Scripps also cited a report from the Los Angeles Times, revealing shipping logs from a disposal company that supports Montrose Chemical Corp. of California, among the largest producers of DDT insecticide in the country. The report details how 2,000 barrels of industrial waste containing the toxic chemical might've been dumped into a designated dumpsite, each month of every year from 1947 to 1961.

Aside from Montrose, other entries in the logs point to other industrial companies in Southern California dumping wastes into the basin until 1972. It was the time when the Marine Protection, Research, and Sanctuaries Act, better known as the Ocean Dumping Act, was signed into law by the US Congress.

Terrill explains that in the surveyed site, they found track-line patterns that suggest dumping being regularly done from an underway vessel like ships or barges. Some of the lines they traced extended as long as 11 miles, approaching state waters.

"While our mapping sonars cannot measure the contents inside the barrels, the target locations are consistent with the previously identified dumpsite and extend much further than we expected," Terrill adds.