Environmental officials revealed a previously unknown area of contamination at the eastern boundary of the Chemtronics Superfund site in Swannanoa at a community meeting on Thursday, Dec. 1.
Contaminants including tert-butyl alcohol and benzene were detected during tests of a monitoring well that borders Bee Tree Creek. Officials said the source of the new contamination so far remains unclear.
Held at the Bee Tree Fire Station, the purpose of the meeting was to discuss public comments regarding the Environmental Protection Agency’s 2016 Record of Decision, or remediation plan, for the site.
Representatives from the North Carolina Department of Environmental Quality and the EPA updated local residents and members of the Swannanoa Superfund Community Advisory Group about the status of the latest plans for the site. Officials also answered questions submitted during a 60-day comment period after the plan’s release in July.
After a brief introduction by CAG President Amy Knisley, the EPA’s Jon Bornholm — who has overseen the site since 1984 — and NCDEQ’s Beth Hartzell outlined changes to cleanup plans for the site.
Back in the day
Since being named a Superfund site in 1982, a series of remediation efforts have sought to clean up six known contaminant disposal areas, as outlined in the EPA’s first plan for the property, which was completed in 1988.
Previous efforts have included capping six disposal areas with impermeable concrete slabs and erecting fencing to prevent exposure and the spread of contaminants. Two separate “pump-and-treat” groundwater extraction systems have also been installed at the site. One system is located in the “Front Valley,” where many of the products responsible for contamination were manufactured; the second is in the “Back Valley,” where Chemtronics and previous site owners, Northrop Grumman and Celanese Corp., tested materials and disposed of toxic byproducts (See “Chemtronics: From Chemical Weapons to Conservation Easement,” March 24, Xpress).
Under the new Record of Decision, the pump-and-treat systems will be eliminated due to a lack of effectiveness, according to Bornholm. Two hundred cubic yards of contaminated soil around former buildings 109 and 116 will also be excavated.
Contractors will remove the excavated soil to an EPA-approved landfill for hazardous materials, said Bornholm, adding that trucks could begin hauling contaminated soil by the end of 2017.
In 2012, the agency introduced a pilot in situ bioremediation program at the site. The program places enhanced vegetable oil fortified with bacteria into contaminated groundwater; the bacteria then consume the pollutants. Bornholm noted the program has produced encouraging results, with up to 90 percent of contaminants eliminated in some test areas. The program will be expanded to take the place of the ineffective pump-and-treat systems.
A public affair
Bornholm and Hartzell also addressed questions and concerns submitted by the CAG earlier this summer.
Major questions and concerns were grouped into several categories, pertaining to future communication between the EPA, the Potentially Responsible Parties or PRPs, the state and the public on progress within the site; the redefinition of the site boundaries and possible future uses of the noncontaminated portion of the property; the placement of institutional controls on the noncontaminated portion of the property under Declaration of Perpetual Land Use Restrictions, or DPLURs; the process of soil removal; the continuation of off-site private well testing for surrounding residents; and strategies to be considered if the bioremediation initiative fails.
Under the new Record of Decision, Chemtronics can split the property into two separate portions, Bornholm said. The 556 acres known to be contaminated will remain under the Superfund designation and will continue to be monitored by the NCDEQ and EPA. The remaining portion of the 1,065-acre property will be restricted to commercial or industrial use, with limitations on public access and guidelines for any future removal or alterations.
Bornholm noted that Chemtronics was considering using the uncontaminated portion of the site for light forestry. The property owners are currently negotiating with the Southern Appalachian Highlands Conservancy to place a conservation easement on the uncontaminated portion, he said.
Michelle Pugliese, SAHC’s land protection director, gave a brief update on the status of those negotiations, saying the organization’s Board of Trustees expected to vote on whether to approve the tentative agreement the weekend of Dec. 3. The board subsequently voted to unanimously approval the easement offering, according to Pugliese.
One community member asked whether the public could expect to have access to this land for hiking or recreational activities. Bornholm said Chemtronics has so far been reluctant to allow public access to the land due to liability concerns. Pugliese noted that, as the property owner, Chemtronics will decide what public access it will allow.
CAG member Jerry Rice, meanwhile, voiced concerns that undiscovered contaminants could lie outside of the redefined 556-acre Superfund site, citing local recollections and rumors of rocket testing and other activities on that portion of the property. “People may have walked and studied that land, but they haven’t lived here and seen those things,” he argued.
Bornholm replied that thorough investigations of the property have not revealed any reason to believe that contaminants may be present in areas outside the redefined Superfund boundaries, but acknowledged that this line of thinking is one of several reasons Chemtronics remains hesitant to allow public access.
Several residents also posed questions about the testing of private wells in the vicinity of the property. Bornholm said environmental consulting firm Altamont Environmental has been “very proactive” in reaching out to neighboring homeowners about water testing. Bornholm assured attendees that the EPA and Altamont will respond to all reasonable requests to test private wells in the vicinity.
Bornholm and Hartzell’s descriptions of positive progress on the site were overshadowed by Bornholm’s revelation that testing conducted in September detected a new pocket of tert-butyl alcohol, or TBA, near the property’s eastern boundary. The contamination was discovered around monitoring well 172-D, which borders Bee Tree Creek. TBA was detected at 120 parts per billion, well above a nondetectable sample taken in March and higher than the state’s interim maximum allowable concentration (IMAC) of 10 ppb. While IMAC levels are enforceable, they are not yet promulgated under state standards. In addition, benzene was also detected at 3 ppb, which exceeds the state standard of 1 ppb for benzene.
Bornholm said that Altamont and the EPA are conducting further tests to verify those numbers and to determine a possible source of the contamination. The EPA is unsure why TBA levels spiked in the most recent sample, he conceded. “It’s not in the [surrounding] deeper or shallower wells,” Bornholm said. “It also hasn’t been detected farther up the watershed. We’re not sure why it showed up, but we’re working on it.”
In addition, Bornholm noted that chloroform and perchlorate had been detected in one of the neighboring private wells sampled by Altamont in October, though those levels did not exceed the state’s acceptable risk limits. While it’s not known where the chloroform originated, he added, the EPA is fairly certain that the perchlorate found in the private well came from the Chemtronics property.
Some audience members questioned whether the emergence of these contaminants might be related to the recent drought conditions; Bornholm reiterated that the EPA was unsure of the cause at this time. Knisley asked that officials continue to update the CAG regarding new findings related to these detections as they come to light.
“Other private wells sampled tested clean,” Bornholm said.
Bornholm explained that the EPA and the Justice Department are drafting a consent decree, which will outline the terms for future remediation and site restrictions.
Once the terms have been finalized, he said, the responsible parties will have 30 days to accept or challenge them. If the responsible parties accept the terms, they will not be liable for any future effects of the contamination.
On the other hand, if the responsible parties reject the agreement, Bornholm said, the EPA will use what he called its “gorilla in the closet” — a unilateral order to implement the 2016 action plan. In that case, he continued, the responsible parties could be subject to future lawsuits related to injury or damages caused by contaminants at the site.
Once a pathway has been finalized, the responsible parties will have approximately 180 to 270 days to implement the remedial design and expand the bioremediation program. Meanwhile, sampling at off-site private wells, including the one where perchlorate and chloroform were found, will continue while the EPA works on its next five-year review of the site, which is due by the end of 2017.
Bornholm closed the meeting with assurances that the responsible parties are being thorough in their efforts to keep the community informed and safe. He added that Altamont will continue to review monitoring wells along the property boundaries for their effectiveness; the consultants could recommend installing additional wells on- and off-site if the existing ones prove ineffective.
For more information about future meetings of the CAG and remediation plans, visit https://goo.gl/gofShn or email firstname.lastname@example.org. For information on the Chemtronics Superfund site, check out https://goo.gl/QEV2m6.