Narrator: This is Science Today. Twenty-five years ago, sea lions on the Channel Islands off the coast of central California had incredibly high levels of DDT in their tissues. After a DDT manufacturing plant in Los Angeles closed in 1970 and stopped dumping the chemical in the ocean, levels started dropping. Researcher Wally Jarman of the University of California, Santa Cruz says the animals now have a hundred times less pesticide in their bodies than they did 25 years ago.

Jarman: The flip side is that we've also been studying peregrine falcons from the central coast of California. There are still very high levels in the sediments and in the dump site that are continually releasing DDT compounds into the environment. And so peregrines on the Channel Islands still have very high levels of DDT compounds.

Narrator: Even more chilling, eagles in the area have such high levels of DDT, they're not reproducing.

Jarman: So that levels in the eagles are so high that it was as if the major manufacturing and spraying of DDT had never stopped.

Narrator: For Science Today, I'm Steve Tokar.