DDT

Peregrine falcon numbers in Yosemite and across the country plummeted from the 1950s to the 1970s due to DDT poisoning.

The water board demanded the cities to submit plans by April to scan these areas for cancer-causing gamma radiation and sample for banned pesticides, including DDT.

The use of the insecticide DDT, as well as habitat destruction, played a significant role in the birds’ decline.

Scientists have found DDT in zooplankton and deep-sea fish off the coast of L.A., indicating the toxic chemical might be infiltrating the base of the food web.

"We are still seeing this DDT contamination in deep-sea organisms and ocean sediments more than 50 years after they were dumped there," said Hoh.