Passive samplers retrieved from offshore DDT barrels dump site

SCCWRP and its partners at Scripps Institution of Oceanography have successfully retrieved passive samplers that were deployed for six months to measure sediment contamination at a former industrial waste dump site in the San Pedro Basin.

The passive samplers, retrieved in March, will support an ongoing effort to measure levels of the pesticide DDT that are diffusing out of seafloor sediment into the water column above. The deployment was the first such attempt to deploy passive samplers offshore following the dump site’s discovery in 2021.

Located between the mainland and Catalina Island, the DDT dump site received thousands of barrels and bulk waste from the former Montrose Chemical Corporation in Los Angeles County, which was at the time the largest DDT manufacturer in the nation.

Passive sampling devices consist of thin membrane films that can detect low levels of contaminants in surface layers of sediment that dissolve into the water column. Sediment contamination poses a potential health risk for marine life and humans who consume bottom-dwelling fish.