The land was soaked with polychlorinated biphenyls from abandoned refrigerators, lead from an 1890s brickyard and all manner of other toxics. Digging out a portion of the 18-acre property, construction workers discovered a railroad bridge — not to mention the usual detritus of concrete, rebar and trash.

Someone standing on the spot — sandwiched between a major interstate and busy CSX railroad tracks, under the flight path of Reagan National Airport and in the shadow of Crystal City — would be hard-pressed to consider it a likely site for an Arlington County park.

But now, after more than a decade of work, the trash-strewn brownfield has been replaced by Long Bridge Park, a startling green sliver of soccer fields boasting artificial turf, separated by permeable concrete, a half-mile-long esplanade and a trellis with an innovative “wave arbor” artwork that responds to wind and light. In coming years, an aquatics and fitness center and another athletic field will take over a weedy field just north of the new park, and advocates hope to create a direct link to the Mount Vernon bike trail.

“This dramatic transformation of a brownfield, industrial site demonstrates Arlington’s commitment to our natural environment and to creating great public spaces that help build community,” County Board Chairman Christopher Zimmerman (D) said in a statement before a ribbon-cutting in November.

Soccer teams have already played a tournament there, and Marymount University, which fully funded one of the large fields, will use it as its home field for soccer and lacrosse games.

It’s not easy to get to: The only access road into the park, at 475 S. Old Jefferson Davis Hwy., is torn up as the county installs sewer and utility pipes and slightly widens and resurfaces it. But this is the last big piece of unimproved open land in the 26-square-mile county. It’s also the most expensive park in the county’s history.

“We [usually] expand our parks by buying the next run-down house” next to existing parks, said Bob Capper, construction manager for the project.

It wasn’t quite so simple here.

Property history

Previously known as North Tract, the land has a complex back story, starting in 1608 when English Capt. John Smith saw the Nameroughquena people hunting, fishing and camping there. The Long Bridge (now the 14th Street bridge) was built in 1808, and shortly afterward Jackson City sprang up, home to gambling dens, houses of ill repute and a racetrack. Civil War forts, a major brick factory and the staging area for the Pentagon’s construction came next.

From 1952 to 1988, Davis Industries ran a scrap yard there, where lead batteries and household “white goods” that leaked PCBs were stored.

In 1993, the then-landowner, the Richmond, Fredericksburg & Potomac Railroad, worked out a deal with Arlington to transfer development rights on the land to another area, so the county took over the North Tract for open space and recreation. A separate agreement with Monument Realty added the site of the former Twin Bridges Marriott hotel to the park. In October, the county board voted to allow Boeing to build its regional headquarters along the park’s border.

Exactly how much pollution is on the site wasn’t known for years, because court files that would answer that question were sealed. But Erik Beach, the county’s Long Bridge Park project manager, said “it was more extremely contaminated than we expected.”

Crystal City resident Rose Mancini told The Washington Post 10 years ago: “You look at the attributes of that area and you say, ‘Are they out of their minds?’ Tell me — on what level does this sound like a good idea?”

She hasn’t changed her mind.

“It looks beautiful, but for where it is and how they use it, it makes me laugh,” Mancini said. “I’d never let small children walk under a jet path, where there’s jet residue, or along a bird sanctuary where there are all kinds of diseases. Some energetic kid is going to climb over that fence to get closer to the railroad tracks. They did a beautiful job. . . . But how are SUVs with three kids going to get in there? You tell me. It’s a treacherous entrance.”

Cleaning up

The road will soon be completed, Beach said, and the site has been made safe for park users. The property twice went through the Virginia Department of Environmental Quality’s voluntary remediation plan; it was approved for industrial use in 2006 and the county reentered the program to establish the site’s safety for recreational use.

Moderately contaminated soil was excavated, treated on-site and then put inside landscape features, such as the walls beneath the 43-foot-high scenic overlook.

Other contaminated areas of the land are now under an asphalt cap and covered by two feet of clean fill. A geotextile cap alerts future construction workers that the land beneath it is contaminated. The area of worst lead contamination is beneath the small paved parking lot, Beach said. The entire park is a “no dig” zone, and the use of groundwater is prohibited to avoid disrupting old contaminants.

“By keeping most of the contaminants on-site, we kept the cost down,” Beach said. Another money-saving idea: About 50,000 cubic yards of the clean fill came from the county’s waste-treatment facility.

The park is paid for with the proceeds of a $50 million bond voters approved in 2004. So far, Beach said, about $30 million of that has gone toward construction and remediation.

On a recent windy, wintry morning, Beach and Capper, the construction manager, showed off wide expansions of playing fields, the fledgling cherry trees and the rooting perennials in the rain gardens. Trainspotters persuaded them to include benches overlooking the railroad tracks, they said. Bird lovers are already seeing great blue herons and eagles, and a large beaver dam is in sight in the adjacent Roaches Run wildlife refuge.

Beach and Capper paused a moment to take in the sights, waited for the noise of a passing jet and a rumbling freight train to abate, then went on discussing plans for completing the park.