Local impact of DDT on deep-sea benthos off Catalina Island
In coastal waters off Southern California, it was common practice in past decades to dump industrial organic pollutants into nearshore and deep ocean water, leaving a legacy of chemical pollution. Recent attention has been given to half a million leaking barrels filled with acid sludge waste from DDT production that were found scattered on the seabed at ~915 meter water depth in the San Pedro Basin near Catalina Island. Initial samples show DDT concentrations in the area far exceed the NOAA sediment quality guidelines and raise concerns about potential effects on benthic communities. DDT (dichlorodiphenyltrichloroethane) was an insecticide that United States banned in 1972 due to health and environmental concerns. USC Sea Grant funded the first quantitative study to investigate the potential impacts of DDT in deep-sea sediments on benthic macrofaunal communities near Catalina Island in terms of abundance, composition, taxonomic diversity, community functional traits, and spatial distribution in the sediment column. The study will determine the actual concentrations of DDT and other pollutants in the sediment.
Key Results:
- Sediment sample cores were collected at an Environmental Protection Agency labeled spot called “Disposal Site 2” at almost 1,000-meter depth near six barrels in August 2021
- Early results show a wide variability between concentrations of DDT and its breakdown products around the six barrels.
- Animals directly associated with barrels contained detectable amounts of DDT breakdown products.
Project Impacts & Application:
- Presentations of data at the 2022 Southern California Regional Chapter of the Society of Environmental Toxicology and Chemistry, the 2022 California Coastal Chloro-Contamination Conference, and the 8th Annual Scripps Student Symposium
Principal Investigator:
- Carlos Neira, Ph.D., University of California, San Diego
- Lisa Levin, Ph.D., University of California, San Diego
Funding:
NOAA, 2022-2024
Additional Info:
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