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Duwamish sludge, from source to sink


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River of no return

A little over three miles from the mouth of the Lower Duwamish Waterway (once known as the Duwamish River), there is a small piece of property wreathed with chain-link fence and signs that warn in various languages of various threats to life and limb. This is Terminal 117, or T-117, former home of roofing material manufacturer Malarkey Asphalt. After the plant closed in 1993, most of its buildings and storage tanks were torn down, but the sediments beneath remained suffused with waste oil, arsenic, polychlorinated biphenyls (PCBs), carcinogenic polycyclic aromatic hydrocarbons (cPAHs), and assorted other harmful acronyms.

This part of the river, as a Port of Seattle official told me, was treated as "Seattle's toilet." With so much shit left to shovel, where will it all go? After all, if we have learned anything from the Duwamish, it is that some histories are easier to dispose of than others.

(1.) Dredge
I am on a small boat with the Port's Kym Anderson and George Blomberg. When Blomberg, an ecologist, looks at T-117, he sees its bright, vegetated future. "Salmon will be able to use it," he says. People will benefit, too. "We're going to put in a boat launch, a pier." Anderson, a chemist by training, is more mired in T-117's complicated present, and thus her view is less rosy. "Cleaning the site is probably impossible," she says wryly. "The water is dirty before it gets here." Even so, the city and state will spend over $30 million trying.

We motor toward a massive dredging barge, its latticed arm reaching for the heavens. A dangling scoop plunges into the brown waters, then resurfaces with sticks and other detritus stubbling its clamped jaws. Water cascades over the rims as the arm swivels to another waiting barge to vomit its load.

As Duwamish cleanup goes, this stage of the T-117 job is small, requiring removal of only 8,000 cubic yards of contaminated sediment. (Overall, more than 70,000 have so far been barged away from the river as a whole.) On this cold February day, the work is about two-thirds done, but crews are rushing to finish: They will have to stop in a week or so, when juvenile chinook salmon start migrating downriver. The fish already have to navigate polluted water. No sense forcing them to navigate much more toxic and roiled mud, too.

(2.) Train
When full, the barge heads to the Lafarge cement plant, near the mouth of the Duwamish. There, the sediments are offloaded, placed in a containment vault, and stabilized with cement kiln dust to remove excess water. Once they are dry enough, they are loaded onto rail cars for one of the great garbage trains that continually circulate around Washington. The train makes many stops, accreting cars of garbage; at the height of dredging, a cleanup might fill 70 rail cars with roughly 2,000 tons of sediments. By the time the train has gathered its full complement – up to 150 cars, with trash from as far away as Alaska – it is well over one mile long.

(3.) Mound
The final resting place, the Roosevelt Regional Landfill, is 250 miles from Seattle, on a plateau that overlooks the Columbia River. On the riverbanks, the garbage trains arrive twice a day and feed their contents to waiting semis. These work their way almost 1,500 vertical feet up a winding road to the landfill. The five-mile round trip takes an hour; drivers might make 10 trips per day.

"You could call us garbage fairies," says Art Mains, the landfill's environmental manager, as he drives me to piles of newly arrived Duwamish dirt. "Out of sight, out of mind." The piles are five or six feet high in places, and spread out over several hundred yards. Flocks of starlings and ravens pick through the refuse; clouds of gulls whirl overhead.

Roosevelt has received tens of thousands of tons of Duwamish sediments since 2003. It isn't the gnarliest waste here, though; the PCB levels are low enough not to need special treatment, and, Mains says, "at (the landfill) we're pretty conservative." With their high-moisture content, the sediments are actually a benefit. The landfill uses them as soil cover, to keep loose trash from blowing all over the place at the end of a shift.

"You'd be amazed by some of the stuff we find in them," Mains says. "Shopping carts, sometimes. Pipes." The sediments contain other things, too: The complicated legacy of industry and growth and civic vision. The evolution of the self-proclaimed greenest city in the country, or one of them, anyway. A reminder that the nature of a river is motion, whether to the sea, or to these elevated mounds several hundred miles inland. The gulls wheel and scream, looking for a place to land.