The Mystery of the Vanishing DDT in the Ocean Near Los Angeles
Posted: March 13, 2013 | By: Maria Cone [Scientific American]
LOS ANGELES – A DDT deposit in the ocean off Los Angeles County has rapidly shrunk, shocking experts and casting doubt on the need to mount a controversial $60-million Superfund cleanup, according to new data.
For decades, government officials and scientists have estimated that 110 tons of the banned pesticide – the world's largest deposit of DDT – have been sprawled on the ocean floor, where it was discharged by a now-defunct Los Angeles company.
But now only about 14 tons remain, according to the latest testing by the U.S. Environmental Protection Agency.
What has happened to the DDT off Palos Verdes Peninsula is, for now, a scientific mystery. Scientists have no explanation for how almost 90 percent might have vanished in a mere five-year period – between tests in 2004 and 2009 – after decades of a slow, gradual decline.
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