Experiment in Burying Undersea DDT Begins

After years of scientific and legal debate, federal officials dropped thousands of tons of silt into the ocean off the Palos Verdes Peninsula on Tuesday, launching an unprecedented experiment to cover a giant underwater deposit of DDT.

Working around the clock, a dredging crew began pumping sediment up from the floor of Long Beach Harbor, then hauling it out to sea and dumping it in 120-foot-deep waters about a mile off White Point.

The project by the federal Environmental Protection Agency is designed to test whether DDT-tainted sediments on the ocean floor can be sealed with a thick layer of mud to protect fish, marine life and people from the decades-old pesticide. If the experiment succeeds, EPA officials hope to launch a massive construction effort in 2002 to cover three or four square miles of the sea floor.

The project is considered risky: Many marine experts fear that capping a pollution site in such deep waters will be exorbitantly expensive and could worsen the problem by stirring up more of the pollution from the ocean floor.

But aboard the dredger Sugar Island on Tuesday, an EPA official said he was pleased with the results of initial tests monitoring the construction.

“With this project, we’re putting a pretty small Band-Aid on a very large wound” said EPA environmental engineer Fred Schauffler. “But the reason we’re out here today is because we want to find out if there is a significant risk to what we’re doing. From what we’ve seen so far, we don’t think there is.”

The experiment will cost $5 million and last several weeks. The amount of silt being dumped will have little immediate environmental benefit. But the test should answer key questions about whether an environmental hazard that has contaminated the ocean for more than half a century can be finally ended.

From 1947 until 1971, DDT manufacturer Montrose Corp., based near Torrance, released pesticide residue into sewers. The area where the sewers flowed into the ocean is now estimated to contain 110 tons of DDT. In 1996, the EPA declared about 17 square miles of the ocean off Palos Verdes a Superfund site, ranking it among the most hazardous places in the United States.

The federal government is seeking about $170 million in damages from Montrose and five other companies in a lawsuit. The case is one of the largest natural resource damage suits in U.S. history. Filed 10 years ago, it is scheduled for trial in October.

EPA officials say that capping the deposit is crucial because the DDT on the ocean floor poses a threat to human beings and wildlife. Trying to dredge up the deposit could spread the pollution and would be nearly impossible.

DDT was a widely used pesticide until it was banned in the United States about 30 years ago. It accumulates in the tissues of marine animals and spreads throughout the food chain. Many birds, including bald eagles and pelicans, nearly became extinct in the 1960s because of DDT’s effects.

In the area being treated, fish such as bottom-dwelling white croaker are contaminated. Despite a ban on commercial fishing around the DDT contamination, federal officials worry that some people are eating the fish. The EPA says that capping the Palos Verdes shelf could reduce the risk to human health by 90%.

The marine ecosystem is also contaminated. Bald eagles on Santa Catalina Island are unable to reproduce without human help because of eggshell thinning from DDT.

But Montrose attorney Karl Lytz has called the capping project “unnecessary, wasteful and potentially dangerous.” Consultants hired by the company say the dumping might create an “underwater avalanche” that would release huge amounts of DDT into the water.

Montrose gathered its forces on Tuesday, sending out its own crew to monitor the project in a small boat alongside the Sugar Island.

EPA officials said they see no evidence so far that anything harmful has occurred.

The work began in earnest Tuesday, although a few dumps were made in early August. Results of tests for DDT in the water column will not be available for a couple of weeks, but video and other tests during the earlier dumps showed that the sediment stayed in a fairly compact load as it dropped to the ocean floor.

“More of it seems to be winding up on the bottom than we thought. We thought we’d lose more in the water column,” Schauffler said.

About 100 loads of silt--an estimated 350,000 tons--will be dumped in the current test at three separate offshore areas, called cells. The EPA scaled back its pilot project from 180 acres to about 135 because of the cost.

For the Sugar Island’s captain, John Lytjen of NATCO Ltd., it was business as usual Tuesday. His crew has dredged harbors around the nation.

For each load, greenish-brown watery sediment--enough to fill a few hundred small dump trucks--is pumped from the bottom of the harbor in a process that takes about an hour. The frothy water fills a giant open hopper--the size of several Olympic-size pools--that takes up half of the 300-foot ship.

Then the crew cruises out to sea to a point about eight miles from the dredge site. At the captain’s signal, the team “cracks the hull”: The bottom of the ship splits open, unloading its huge cargo of silt in just a few minutes. A plume of dirty-looking water on the ocean surface circles the ship, spreading only about 200 feet before dissipating.

Then the crew heads back to Long Beach Harbor to do it all again. Each load takes about four hours.

Picking up muck from the ocean floor and moving it a few miles may seem like an exercise in futility. But both ends of the operation are potentially valuable.

Silt is clogging the Queen’s Gate channel at the entrance of the Port of Long Beach, preventing large ships from reaching the harbor. So the Port of Long Beach has hired NATCO to dredge the channel. The EPA is using a small amount of the dredged sediment--which tested fairly free of contaminants--to construct its cap over the DDT site.

For this project, the only unusual activity for NATCO’s dredging crew was the extent of the EPA’s monitoring to see exactly where the dumped sediment lands and how much bottom silt it stirs up.

Because of the experimental nature of the deep-water dumping, the EPA is conducting an unusual number of tests. An EPA-hired boat riding alongside the dredger has cameras on the sea floor, sonar devices and equipment to collect sediment cores. The ocean floor is monitored for at least two hours after a dump.

Dredging up silt and dumping it in marine waters is nothing new for the EPA. But the waters off the Palos Verdes Peninsula are at least three times deeper than any other Superfund project, such as those in Boston and New York harbors.

The EPA is trying out two types of silt and two techniques for dumping it. The material used Tuesday is fairly coarse and was dumped in one quick load. Later dumps will use finer silt from a different dredge site and attempt to spread it in a slower, more costly process.

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DDT Capping Test

The U.S. Environmental Protection Agency has begun covering a small portion of the ocean floor off Palos Verdes Peninsula with silt in an experiment to see if a large deposit of DDT can be sealed. Three small plots will be covered in this test, and if that works, the full project could encompass as much as four square miles of the ocean floor.

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DDT Deposit Facts

From 1947 to 1971, a pesticide plant near Torrance routinely discharged DDT into sewers that flow into the ocean.

110 tons of DDT are in ocean sediment.

The contamination is spread across 17 square miles of ocean floor, 1-2 miles offshore in waters as deep as 230 feet.

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Capping Project

The area totals about 135 acres in three separate plots.

Cost is roughly $5 million.

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Source: U.S. Environmental Protection Agency