Team to attack mercury in South River

Mike Liberati stands on the eroding, mercury-infested South River bank within sight of the nearly-deserted Invista plant, hopeful that a pilot project to begin Tuesday will help stabilize a 500-foot riverfront area while eliminating the hazardous material from entering the water.

If successful, the South River Science Team, the project’s organizer, hopes to replicate it all along the river where mercury from the former DuPont plant has contaminated the soil.

Because too much mercury seeps into the river, the Virginia Department of Health has fish consumption advisories that have been in effect since the 1970s. Mercury was used, legally, at the former DuPont plant from 1929 to 1950.

A 1980s study estimated that more than 100,000 pounds of mercury went into the river and surrounding floodplain. The mercury impairment extends more than 150 miles downstream from the Waynesboro.

DuPont is obligated, under a settlement between it and the State Water Control Board, to keep a trust fund in place to support a 100-year monitoring program for mercury. 

Liberati, senior project director for DuPont, said he has seen the area above the riverbank flood, and a goal of the project is to make sure that doesn’t happen.

“The challenge is to build something to withstand that kind of impact,” Liberati said.

Don Kain, water compliance and monitoring manager for the Virginia Department of Environmental Quality, said it was key to attempt the project now because the river is at a low-flow level this time of year. DEQ’s role in the project, he said, is not regulatory.

“We’re partners in exploring the science with DuPont and the other folks with the South River Science Team to find the best solutions, the best answers, the most workable approaches,” Kain said, “to managing and controlling mercury, and ultimately, to reduce the risk to those using the river.”

However, cost could be an impediment to future riverbank stabilization, Liberati said. To date, DuPont has spent several million dollars and, on the current project, more than $350,000 in design and construction costs.

He is not sure of the project’s final cost and hopes to find efficiencies that can be applied should the pilot project be successful.

With many stretches of eroding riverbank facing the same mercury infestation, he said they’ll need help to pay for and find other ways of keeping the mercury out of the water. DuPont, though, still owns the land surrounding the Invista plant and bears responsibility for cleaning it up.

The key elements of the project include removing the vegetation from Rockfish Run to the Invista parking lot. Erosion control measures will also be established.

Then, crews will work in the river itself, putting in wooded debris – tree logs and root masses – that will be bolted into the rocks. The riverbank will, at that point, be covered with lifts of soil that will be encapsulated with biodegradable coconut mesh nets.

“One objective is to not move soil, so we’re going to leave the natural grade of the bank and build out upon it,” Liberati said.

Native vegetation will be planted after that to stabilize the soil, help prevent erosion and restore and expand the habitat.

The South River Science Team has been working for 18 months with Inter-Fluve, Inc, a Hood River, Oregon company, The company specializes in sustainable design, restoration and construction of river ecosystems.

Inter-Fluve came up with the project’s design and will be providing construction guidance on the project.

The local Virginia chapter of Trout Unlimited has also given input to the project’s design.

“It’s kind of like the Cadillac design,” Liberati said. “We’re trying out a lot of different techniques in this one, 500-foot effort to see what’s going to work best.”

Liberati said the area they will be working on is ideal because the eroding bank there has high levels of mercury contamination and there is good construction access.

The science team will measure mercury levels in the water, river sediment and aquatic organisms before and after the project.

The goal is to complete the work in the water by the end of September to allow for the state Department of Game and Inland Fisheries to stock the river with trout. From there, the project will move to the riverbank through October, when it is the better time to plant, Liberati said.

No equipment is expected to be in the river during the project.

“If the pilot project is successful, this same technology may have applications at other locations up and down the river,” Kain said.

Liberati and Kain hope for a toolbox of remediation technologies that can limit the impact of the mercury to the point where, someday, the advisories can be removed.

DEQ says there needs to be a 99 percent reduction in mercury levels, or less than 2,029 grams of mercury per year entering the river, which is known as the total maximum daily load.

Once the property is cleaned up to the satisfaction of DEQ and the Environmental Protection Agency, the property will then be turned over to Invista.

Kain also has another goal for the project of trying to find a way to manipulate the methylation cycle of mercury – where it turns from a less harmful elemental form to a more dangerous methylmercury.

“We’ve studied, we’ve communicated, but there hasn’t been an on-the-ground project that actually tested some of what we learned and tried to determine if this will make a difference,” Kain said. “There’s so much to learn.”