A new Times' investigation is unraveling a toxic mystery in the coastal waters off Catalina. It is a tale of how the ocean became a dumping ground for DDT, a now-banned pesticide, which mostly remained a buried secret until a new generation of scientists discovered it.

LA Times Environmental reporter Rosanna Xia wrote about the findings. 

There are so many toxins that affect humans' and animals' lives, but DDT is the original chemical that shocked the public back in the 1960s.

"The largest DDT maker in the world was based next to Torrance, California. The DDT manufacturer got rid of its waste, which contained DDT, by dumping it through the sewage pipes about two miles off the Palos Verdes' coast. The way the manufacturer got rid of DDT was by taking DDT barrels into the water near Catalina and dumping them directly into the ocean. I found reports from the 70s and 80s that stated that if the barrels did not sink, they would take an ax to puncture them to make sure they sank to the seafloor," said Xia.

DDT can take decades and generations to break down.

"We're still living the long term impact of what it means to have small doses of these chemicals in our bodies. A lot of the science is still ongoing, but one thing that is unique about DDT is that mothers can pass this chemical on to their children. We see this with marine mammals like dolphins and sea lions, who also accumulate these chemicals over a long course of their life. They're a vital indicator species of what it means for mammals and the health of our oceans in general," added Xia.

The impact of DDT starts from the smallest organisms and moves up our food chain.

"Think about the smallest animal, the phytoplankton in the ocean with DDT in it. Then, the fish would eat lots of phytoplankton, and bigger fish would eat those fish. As we move up the food chain, dolphins and sea lions are on top of the food chain, and so are bald eagles, falcons, and condors. When they eat all these fish with DDT in it, it accumulates the chemicals in their bodies, and has a lot of concerning impacts," said Xia.

When it comes to mammals and humans, DDT is affecting their hormone and immune system.

"Regarding bald eagles, people might remember that DDT causes the eggshells of a lot of birds to be so thin that they crack, and the chicks don't survive. You suddenly stop seeing all these birds in our skies. That's where Silent Spring comes from," said Xia.

A University of Santa Barbara scientist discovered this latest trove of dumped DDT barrels. 

"David Valentine, this researcher at UC Santa Barbara, had heard these whispers about the barrels dumping in Catalina for years. He was on a research mission with these deep-sea robots for a different mission, but they were ahead of schedule, so they had a little extra time. He dropped the robots down 3,000 feet into the water and came across these barrels. It was a surreal moment," added Xia.

Tia said there could be as many as half a million barrels of DDT waste still on the sea floor right now. Finding a solution to clean up these barrels is not an easy task.

"It's so complicated, I tried to ask every scientist that I talked to about possible solutions, and it's not as easy as taking these barrels out of the water. It is 3,000 feet deep, there is a big pressure difference, and these barrels are leaking. When I asked the U.S. Environmental Protection Agency about possible solutions, they declined to comment. I plan on following up, and there are several other agencies and legislators we could be talking to as well," said Xia.