Many fish caught off Los Angeles County still contain extremely high levels of DDT, a sign that anglers and consumers remain at risk and that the ocean's ecosystem may be far from recovery 35 years after the pesticide was banned.
Newly released data from a federal survey indicate that fish caught in the area contained the world's highest-known DDT concentrations. Among 1,200 fish caught from Ventura to Dana Point, white croaker off San Pedro and the Palos Verdes Peninsula were the most highly contaminated. Fish off Orange County and areas north of the Redondo Beach Pier had low concentrations.
The data, collected primarily in 2002, offer the most comprehensive look at the scope of contamination from a 100-ton deposit of DDT that still covers several square miles of the ocean floor decades after the pesticide flowed into county sewers beginning in the late 1940s.
More recent annual sampling by Los Angeles County, far less extensive than the federal survey, suggests that the DDT levels in fish may be improving but still far exceed safe levels.
In response to the new federal findings, the state's environmental health agency is reevaluating the risks of eating locally caught fish, which could result in updates to a health advisory and a commercial fishing ban that have been in effect since 1991.
Fish from local waters are often eaten by recreational anglers and subsistence fishermen, who catch them from piers and boats. Some highly contaminated white croaker is still showing up in a handful of Asian markets in Los Angeles and Orange counties.
The levels "are lower than what we historically have seen" in the 1970s and '80s, "but they are still levels of concern to us," said Sharon Lin, a Superfund project manager at the Environmental Protection Agency's San Francisco office.
Banned in the United States in 1972, DDT is classified as a probable human carcinogen and has been linked to liver disease, reproductive damage and altered hormones in lab animals and wildlife. So much DDT remains in bald eagles on Santa Catalina Island that their chicks die unless the weakened eggs are removed from the island to hatch.
The data from the federal survey by the National Oceanic and Atmospheric Administration and the Environmental Protection Agency suggest that there has been no improvement since the late 1980s, when the last regional fish survey was conducted. Some scientists have long theorized that the DDT on the ocean floor has been breaking down into less-toxic compounds and would soon disappear from marine life.
