Cleaning a River That Was Given Up for Dead

In 1984, when the Environmental Protection Agency put the old Diamond Alkali factory in Newark on its list of the most heavily polluted places in the country, the agency was not thinking about the Passaic River, which runs right in front of the plant.

The company made Agent Orange during the Vietnam War. The factory had spread deadly dioxin, a crucial ingredient in the defoliant-, all over the surrounding neighborhood, a jumble of businesses, industries and private homes.

“There was dust in the homes and on the streets that had to be cleaned up,” recalled Walter Mugdan, head of the Superfund program in Region II, which includes New York, New Jersey and parts of the Caribbean. At first the agency did not feel the need to expand its work from the upland part of the Diamond Alkali site to the river itself. But as I relate in an article in The Times, over that changed overtime.

“Only in the following decades did we start following the trail that starts directly in front of the plant,” Mr. Mugdan said. Eventually investigators realized that the dioxin had spilled from the plant into the river. Vigorous tides pushed the contamination downriver while saltwater tides from Newark Bay that were just as strong pulled the dioxin miles upriver.

Investigators kept following the ever-enlarging trail. “”When we got to six miles up and six miles down, we said “Let’s take a look at the entire river,” Mugdan said. “Only slowly did we come to the realization and recognition that the problem extended from Newark Bay to the Dundee Dam,” a total of 17 miles.

That the Diamond Alkali site originally referred to just the upland portion and the aerial extent of the contamination emanating from the land is a strong indication of how narrowly the Superfund program was initially focused. Of course, over time, the area subject to the law grew and grew.

But acknowledging the extent of the contamination was just the agency’s first challenge in tackling a project as big as detoxifying a river, especially a river that was as abused as the Passaic, one of America’s first industrial waterways.

In the late 18th century, Alexander Hamilton founded an industrial city in Paterson that ran on the power of the Great Falls of the Passaic. In the 19th century, hundreds of industries sprouted on the river’s banks in Newark and many smaller communities. Dumping industrial waste into the river was not illegal then, and as a result it became so polluted that it basically was left for dead.

“The comeback of rivers like the Passaic simply could not be envisioned” when Superfund was created in 1981, said Eric. A. Goldstein, the New York City environment director for the Natural Resources Defense Council.

For many years the prospect of cleaning up the Passaic was so daunting that nothing was done. Only recently has the technology, and the legal willpower existed to force the polluting companies and their successors to start discussing a cleanup.

Even then, the details are so devilishly complex that it has taken years to come up with a plan of attack, based on the old medical axiom of “First do no harm.” As Raymond Basso, head of the E.P.A.’s Passaic River cleanup, has said, “We definitely don’t want the cure to be worse than the disease.”

The technology being used on the river isn’t much different from what might have been used half a century ago. The polluting gunk has to be dredged out and disposed of, although now global positioning satellites guide the dredges.

But removing the contaminated sediment disturbs the poison that lies in the mucky river bottom and tends to spread it even farther.

And there’s another challenge. It’s hard enough to clean an urban waterway when there’s one pollutant of concern, as with the Hudson River, where the E.P.A. is overseeing General Electric’s removal of sediment contaminated with PCBs that the company dumped there decades ago.

But in the Passaic, the list of pollutants is almost as long as the list of companies responsible for the contamination. At latest count, more than 70 companies were on that list. Besides dioxin, the pollutants include PCBs, mercury, DDT and heavy metals.

Adding to the complexity is the character of the Passaic, a tidal tributary. It has tides in two directions, like the East River, with saltwater incursions that reach as far as the Dundee Dam in Garfield, 17 miles upriver. The saltwater tends to stay on the bottom, with the fresh water coming down river on the surface, creating two-way traffic that resembles the bus lanes into the Lincoln Tunnel during rush hour. In addition, the Passaic is notorious for regular flooding, which tends to move the polluted sediment farther and faster than the tides.

To figure out the best way to treat a polluted waterway, E.P.A. specialists rely on complex computer modeling to take into account all the possibilities and then predict how various alternatives would affect the river.

These are some mighty complex calculations. To predict what will happen to the sediment in the Passaic, the agency’s computer modelers have studied myriad aspects of the river itself, focusing on 11 variables including river flows, salinity and temperature, as well as rates of dispersion, degree of turbulence, and the concentration of solid particles in the water.

Modelers then take into account the huge area of the Passaic that is believed to be contaminated. They plot the area on a grid map that includes both water and sediment, and then divide it into approximately 23,000 active grid cells.

All that data, and a whole lot more, is fed into supercomputers. The model being used on the Passaic can make a single calculation about once every 10 seconds, which is equivalent to around 720 billion calculations for every one of the years into the future being studied. The model predicting how the sediment will move when disturbed carries out to 30 years from now. To come up with predictions, it takes more than 21 trillion calculations.

And consider this: Sediment transport is just one part of the overall projections for the Passaic. The E.P.A. also will have similar computer runs for carbon production and contaminant fate. When they are all put together in the proper ratios, this adds another 21 trillion calculations.

In all, from the time the data is loaded, the computers have to run for an entire month before they can spit out a set of projections.

“It’s the modeling and predicting the future that’s harder than anything,” Mr. Basso said.

Communities like Newark’s Ironbound and others along the river have been waiting for more than 30 years for the cleanup of the Passaic to begin. At the same time the companies that are on the hook for paying for the very expensive cleanups want certainty that dredging is the best option. Getting the modeling right takes time, and it’s often necessary for the Agency to ask both sides to be patient.

“It’s really hard to stand before the public and say we need a few more months to complete our models,” Mr. Basso said.

On the other hand, he said, he knows that “when you ask someone to spend millions to clean up and it’s not cleaned up to the level that’s expected, that makes national headlines.”