Western Washington University professor completes study of mercury contamination in South River

south riverThe South River flows along the western foot of the Blue Ridge Mountains, coiling its way across bucolic rolling farmlands and through small towns, marching north to join first the Shenandoah and then the Potomac before eventually emptying into the Chesapeake Bay.

With its load of fresh water drained from lush mountain valleys with names like Cool Spring Hollow and Gum Springs, the South River carries with it a toxic tide: mercury, dumped into the watershed for more than 20 years from the DuPont Chemical Co.’s Rayon plant in Waynesboro.

For the past five years, Wayne Landis, director of Western Washington University’s Institute of Environmental Toxicology and professor of environmental sciences, has worked to understand how the mercury in the South River affects humans as well as the fish and animals that live in and along it. Assisting him has been a corps of graduate students, each adding their research to the work of a team consisting of state and federal environmental agencies; the Army Corps of Engineers; environmental nonprofits such as Save Our Streams and the Chesapeake Bay Foundation; DuPont; and other academic institutions such as Virginia Tech, James Madison University, and the University of Delaware.

Tasked with providing the funding needed for research and remediation of the South River, DuPont contacted Landis to work on an environmental assessment of the river as well as to put together a framework strategy for how the river could be most safely used for fishing, boating and recreation.

After five years and about $500,000 in grant funding for this work from DuPont, Landis said this first stage is almost complete.

“The thing about mercury is that it doesn’t go away, or degrade,” said Landis. “Once it’s there, it’s there to stay until it is removed. Flooding on the South River takes the mercury from the sediment and deposits it along the flood plain or high up in the banks, where it binds with the soil, so it’s not just the area right next to the plant that is at risk.”

For more than 20 miles downriver from Waynesboro, public lands along the banks are posted with signs warning against eating any fish caught there. Microbes ingest mercury from the sediments, and this mercury bio-accumulates as it goes higher and higher in the food chain, up to the river’s largest fish predators such as smallmouth bass. What this means is that the river’s smallmouth are ingesting and storing every bit of mercury previously ingested by the creatures down the chain.

Landis said removal of toxic sediment isn’t the cure-all that it seems. Disturbing the sediment can potentially release mercury back into the watershed, as removal is a tricky process, and armoring the banks of the river is not only very expensive but it removes valuable habitat for many of the animals that live there and could further devastate the ecosystem.

“What we are working towards is finding a strategy for human use that is realistic and safe – tourism, recreation and fishing are huge parts of the local economy – while at the same time understanding exactly how this mercury is affecting the ecosystem,” he said.

Landis and his team tracked data on four species common along the South River to better understand how they are faring in the face of the mercury contamination: smallmouth bass, white sucker, Carolina wren and Belted Kingfisher. Not too surprisingly, the two species that live in the river – the white sucker and the smallmouth bass – showed the highest amounts of mercury.

Besides his own work on the project, Landis has been able to place a number of his graduate students into the project, such as Meagan Harris, who recently completed an analysis and threat assessment for the South River Science Team (SRST) on how the South River’s mercury load impacts both the environment as well as recreational uses such as fishing and boating.

The realities of the South River are now clear to most ­– that mercury will be in the South River watershed for generations to come. Landis says what he and his team are working to accomplish is to provide the state, federal and local agencies working on the river with a tool they can use to best understand how to move forward.

“This is a case study, and we want to use it as a way to set up a long-term monitoring system that can be used as a blueprint for how others can move forward,” he said. “There are dozens of Waynesboros out there, whether it’s mercury or PCBs or something else. And they’re all wondering how to get started, and how to move forward in the long-term – and that’s where threat assessments and plans like these can be used. It’s a template for helping understand environmental risk.”

DuPont’s Ralph Stahl said Landis and his team have provided a tool that the SRST can use to better understand how risk-management actions can be used to improve conditions in the watershed.

“We really value the partnership we’ve had with Dr. Landis and his students,” said Stahl.

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