Loudoun County, EPA Differ on Hidden Lane Cleanup

Loudoun County supervisors have asked the Environmental Protection Agency to reconsider its plans for the cleaning up of pollution at the Hidden Lane landfill after an independent consultant reported the approach could produce an even more toxic substance.

The Hidden Lane site, a former landfill, has been on the EPA’s Superfund list of most contaminated sites since 2008, after it was found to be leaking degreaser into nearby homes’ well water. The dump had been closed by court order in 1983 after a legal battle with the county, which had never issued a permit for the dump.

Nearby homes were equipped with water filtration. In 2017 the estate of the former owners reached a settlement with state and federal authorities to help fund the cleanup by selling the land, and in 2019 the EPA announced it would pay to connect 124 homes in the Broad Run Farms neighborhood to public water, work that is ongoing. A developer has also now proposed new housing around the site.

The EPA is nearing approval of a plan to clean up the source of the contamination, with other plans still in the works to clean up the site-wide groundwater contamination. Part of that plan involves adding other chemicals to encourage natural microorganisms on the site to passively break down and treat the contaminants—a plan that Virginia Tech professor and head of the university’s Department of Civil and Environmental Engineering Mark Widdowson wrote has a poor track record of success.

In fact, he wrote, the plan could release dissolved vinyl chloride into the groundwater—a more toxic and potent substance than the degreaser the cleanup is targeting, trichloroethylene.

“It is not scientifically defensible to expect significant TCE mass reduction in bedrock can be achieved by relying on source zone microorganisms and/or chemical reductants,” Widdowson wrote in a report to the county government. “The use of In SituBioremediation and Chemical Reduction in bedrock aquifers does not have a strong track record of success at other Superfund sites.”

Instead, he recommended other options under consideration that would involve injecting strong chemicals into the site to break down the contaminants, or that would heat the contaminants to boiling temperatures, trap the vapors and take the substances somewhere else for safe disposal.

“it’s going to produce more toxic byproducts than what we have there now, and that just seems stupid,” said Supervisor Michael R. Turner (D-Ashburn).

Widdowson also found the EPA’s plans in some parts were poorly defined, with differing thresholds for cleanup in a feasibility study and the proposed plan, and not covering all the contaminants in the site.

The county’s preferred options are more expensive; preliminary estimates put the EPA’s preferred option at $5.9 million, while the county’s preferred options are estimated at $11.1 million for the chemical injections and $27 million for boiling off the contaminants. The federal government will fund the cleanup.

County supervisors asked the EPA to consider those options at their meeting June 1. While the EPA is required to solicit feedback from the locality, it is not required to heed their recommendations.

Supervisors voted 7-0-2, with Chair Phyllis J. Randall (D-At Large) and Supervisor Caleb A. Kershner (R-Catoctin) absent.

“I already expressed my gratitude to staff, but I‘m also very thankful that county admin had the foresight to hire an independent consultant such as Mr. Widdowson to advise us and sort of be a check on the advice that we’re getting, or the suggestions that we’re getting, from the EPA,” said district Supervisor Juli E. Briskman (D-Algonkian). “I know the community appreciates it as well.”

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